Peanut Butter Chocolate Mousse Cake

This Peanut Butter Chocolate Mousse Cake starts with a layer of brownie topped with mini Reese’s, then topped with a layer of peanut butter mousse, then a layer of chocolate mousse. It is rich, delicious, and yet light because of the mousse. Absolutely to die for!

Peanut Butter Chocolate Mousse Cake on a blue cake stand with a slice removed

Peanut Butter Chocolate Mousse Cake slice on a plate

This cake was actually our dessert for Super Bowl Sunday last week. I had something else I was going to share with you today, but I just couldn’t wait to give you guys this recipe!

I think I mentioned that we had our small group over for the Super Bowl. Well, we had a birthday to celebrate and it was requested that it somehow involve Reese’s. This cake is what I came up with.

I’ve decided that I love the requests I get for this particular birthday. Last year, the inspiration was some kind of cannoli dessert and I made this Cannoli Poke cake. It ended up being my most viewed recipe of all the ones I posted in 2014. Perhaps they are good luck charms? 😉

Peanut Butter Chocolate Mousse Cake on a blue cake standPeanut Butter Chocolate Mousse Cake slice on a plate

So while I recognize that this cake may not seem simple, and I know it has several steps involved, the truth is that it’s not hard to make. My mom would disagree, as she is not a baker and doesn’t even own a springform pan (which is needed to make this cake), but it really is doable.

I started with a box brownie mix. You could definitely replace it with a brownie from scratch, but usually when a cake has several steps like this, I try to cut a few complications out by using a boxed brownie. It’s just how I roll. But if you aren’t a fan of boxes, definitely go for a homemade one. I love this Quick and Easy Brownies recipe.

The mousse layers are based on the mousse from my Funfetti Millionaire Cake – one my favorite cakes ever! It’s nice because you don’t have to use your stove, just a little bit of microwave use. You will need to use some gelatin to help stabilize it. Don’t be afraid of gelatin if you haven’t used it before. It comes in a powder and isn’t as scary as it seems. Let break the mousse down.

Peanut Butter Chocolate Mousse Cake slice on a plate

To make the mousse, first sprinkle the gelatin powder over cold water. You want to sprinkle it out over the water, not pour it in a big pile. This allows to gelatin to bloom, or hydrate, before adding to the recipe.

While the gelatin sits, heat the heavy cream in the microwave until it comes to a full boil. The gelatin is added to the heavy cream and the heat activates it. The gelatin should be whisked into the heavy cream. The heat should help it dissolve so that you don’t have any lumps.

Pour the hot cream over the peanut butter chips and let it sit for a few minutes to soften the chips. Whisk that mixture until smooth – much like making ganache.

The next step is to make whipped cream. It’ll be added to the ganache mixture in two parts. Once everything is combined, it’s added to the pan with the brownie. The peanut butter mousse is added first, allowed to firm up a bit so that the next layer can be added, then the chocolate mousse tops it off.

I finished the cake off with some chocolate whipped cream and more mini Reese’s. I made a fairly thin layer of whipped cream, but you could easily double the recipe if you want more. The cake makes a beautiful presentation and is absolutely delicious. The brownie is the perfect thick and chewy base to the light mousse layers. Yum!

Peanut Butter Chocolate Mousse Cake on a blue cake stand

You might also like:

Peanut Butter Chocolate Buckeye Cupcakes
Peanut Butter Chocolate Chip Macaroons
Mini Reeses Peanut Butter Cheesecakes
Loaded Peanut Butter Layer Cake
Peanut Butter Cookie Dough Brownie Layer Cake
Peanut Butter Cake with Chocolate Cream Cheese Frosting

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Peanut Butter Chocolate Mousse Cake with slice missing
Recipe

Peanut Butter Chocolate Mousse Cake

  • Author: Lindsay
  • Yield: 14-16 Slices
  • Category: Dessert
  • Method: Oven
  • Cuisine: American

Description

A chewy brownie topped with mini Reese’s, peanut butter mousse, and chocolate mousse.


Ingredients

BROWNIE LAYER

  • 18.4 oz box brownie mix (for 8×8 pan)
  • 8 oz bag mini Reese’s

PEANUT BUTTER MOUSSE

  • 1 tsp + 1/8 tsp powdered gelatin
  • 1 1/2 tablespoon water
  • 9 ounces peanut butter chips
  • 2 1/4 cups heavy whipping cream
  • 1/4 cup powdered sugar

CHOCOLATE MOUSSE

  • 1 tsp + 1/8 tsp powdered gelatin
  • 1 1/2 tablespoon water
  • 9 ounces semi sweet chocolate chips
  • 2 1/4 cups heavy whipping cream
  • 1/4 cup powdered sugar

CHOCOLATE WHIPPED CREAM

  • 1 1/2 cups heavy whipping cream
  • 1/4 cup powdered sugar
  • 1/4 cup natural unsweetened cocoa (I used Hershey’s Special Dark Cocoa)

Instructions

NOTE: A 9 inch springform pan is best for this recipe so that you can easily remove the cake once it’s been assembled.

BROWNIE:

1. Make brownie dough according to instructions on back of box.
2. Grease a 9 inch pan (preferably springform pan, see above) and line the bottom with parchment paper to allow for easy removal. Pour brownie batter into pan and bake according to box instructions.
3. When brownie is done baking, remove from pan and allow to completely cool.
4. Once brownie has cooled, place brownie back into the bottom of the springform pan. Line the sides of the pan with parchment paper that sticks a few inches above the top edge of the pan.
5. Top brownie with an even layer of mini Reese’s. Set aside.

TO MAKE PEANUT BUTTER MOUSSE:

1. In a small bowl, sprinkle the gelatin over the water, let stand for about 5 minutes.
2. Place the peanut butter chips in a medium bowl
3. Microwave 3/4 cup of heavy cream until it comes to a full boil.
4. Add gelatin mixture to the heavy cream and whisk until dissolved.
5. Pour cream over the peanut butter chips and let sit for about a minute.
6. Whisk until peanut butter chips are melted and mixture is smooth. Set aside, cooling for about 5 minutes.
7. Whisk remaining 1 1/2 cups heavy cream at high speed with a mixer until it begins to thicken.
8. Add powdered sugar then continue to whip until stiff peaks form.
9. Fold about a third of the whipped cream to the lightly cooled peanut butter mixture until well combined.
10. Add remaining whipped cream and fold in until well combined.
11. Spoon mousse evenly over the brownie and mini Reese’s and spread evenly. Place in refrigerator for about 1-2 hours, until firm enough to add another layer.

TO MAKE CHOCOLATE MOUSSE:

1. In a small bowl, sprinkle the gelatin over the water, let stand for about 5 minutes.
2. Place the chocolate chips in a medium bowl
3. Microwave 3/4 cup of heavy cream until it comes to a full boil.
4. Add gelatin mixture to the heavy cream and whisk until dissolved.
5. Pour cream over the chocolate chips and let sit for about a minute.
6. Whisk until chocolate is melted and mixture is smooth. Set aside, cooling for about 5 minutes.
7. Whisk remaining 1 1/2 cups heavy cream at high speed with a mixer until it begins to thicken.
8. Add powdered sugar then continue to whip until stiff peaks form.
9. Fold about a third of the whipped cream to the lightly cooled chocolate mixture until well combined.
10. Add remaining whipped cream and fold in until well combined.
11. Spoon chocolate mousse evenly over the peanut butter mousse and spread evenly. Place in refrigerator for about 2-3 hours, until completely firm.

TO FINISH OFF CAKE:

1. Make the chocolate whipped cream: Whisk 1 1/2 cups heavy cream at high speed with a mixer until it begins to thicken.
2. Add powdered sugar and cocoa and continue to whip until stiff peaks form.
3. Take mousse cake out of the springform pan and place it on serving plate or cake circle.
4. Icing the outside of the cake with the chocolate whipped cream.
5. Garnish with additional mini Reeses. Refrigerate until ready to serve.


Enjoy!

Peanut Butter Chocolate Mousse Cake - A brownie layer on bottom with Reese's, topped with peanut butter and chocolate mousse!

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Recipe rating

104 Comments
  1. Momof3

    I made this with my daughter for my husband’s birthday — had to improvise slightly (used a bread loaf pan and used regular peanut butter, cream cheese and powdered sugar for the mousse). It was a major hit!

  2. Vicki

    Delicious! This was a big hit! Instead of chocolate whipped cream, I topped it with a chocolate ganache, then piped peanut butter whipped cream around the edge before topping with the mini Reese’s. It was slightly too tall for my springform pan. Next time I’ll either use an acetate collar or use my wider pan and adjust the baking time for the brownie.

  3. Patty

     Tried to even add food coloring to The Who cream with cocoa powder and it does not look as dark as your frosting😞 

  4. Sheree Baty

    Is there a reason yiu picked a brownie base over a chocolate cake? I have a dense chocolate cake recipe, have you tried it?

    1. Lindsay

      It’s been along time since I created this recipe so it’s hard for me to remember my exact thought process. But a brownie or a cake on the bottom should work well.

    1. Lindsay

      I’m so sorry for the trouble! There was an issue today that affected thousands of sites – mine included. It looks like it’s been resolved, so you should be able to access it here now. Sorry about that!

  5. Amy S Growney

    YUMMMM!!! My husband loves peanut butter and mousse. This cake was made for him. Certainly didn’t turn out looking as nice as the picture above, but man was the taste there!! Yes, there are a lot of steps, but they are all easy. I made it over two days with my 3 year old son — even whipped some cream with my 10 month old on my hip. Don’t be intimidated by all the layers, it’s doable and worth it. My husband said it was the best cake he ever had. Thank you Lindsay for another memorable birthday cake =)

  6. Tasmin

    I just made this recipe for a baby shower but did them in cups. I used premade two bite brownies for the bottom layer and just flattened them a bit first. Then the pb layer and chocolate layer and then sprinkled them with dirt (oreo crumbs) as it was lumberjack themed. They were amaaaazing! Thanks for the wonderful recipe! I tripled it and it was still easy and came together beautifully.

  7. Nurit Philip

    I love your cakes , every time I see your post I want to run to the kitchen and make it. I have used your chocolate cakes as a base for the cake I design.
    Thank you

  8. Angel

    Echo others’ comments about how AMAZING this cake is! Have used the chocolate whipped cream as a frosting now a few times using the Hershey’s Special Dark and, while absolutely AMAZING in texture, beautifully pipeable, and wonderful in flavor, it is still a very light brown like the chocolate mousse layer. Like others have said, it is not even CLOSE to the rich dark brown in your pictures. Any idea what you did differently?

    1. Lindsay

      So glad you enjoyed it! I really don’t know about the darkness. Maybe it’s just the way the photo captured it? I just used the dark cocoa. I think it also sat in the fridge for a bit before I took the photos and I know that chocolate whipped cream tends to darken as it sits. But otherwise, I didn’t do anything differently.

    2. Lindsay

      I’m really not sure or I’d share it. I do believe the whipped cream darkens as it sits in the fridge, so that could deb what happened. I believe it was refrigerated for a day before I took the photos.

  9. Jane

    I’ve commented on this recipe before, but I just made this for my daughter in laws birthday and for health reasons she’s gluten free. The only thing I did different was swap out the brownie layer for a flourless chocolate cake instead. What a success! Even her son, who swears he “hates” peanut butter actually picked up his plate and licked it clean – right there in the restaurant lol. Ty for helping me let her celebrate without the pain from eating gluten!

  10. Julie Lawson

    I am searching for recipes for a wedding reception. The groom is a big chocolate and peanut butter lover. This looks like a great “cake” but am wondering about transporting this cake in the hot Georgia summer weather. Has anyone frozen this cake after it was made? I am thinking that I will partially freeze all of the cakes to help with transporting. They will thaw by the time they’re in the reception hall. Thanks, in advance, for any advice.

    1. Lindsay

      It could be worth trying. The only thing to think about is the condensation from the thawing. It could cause colors to run and things like that.

  11. Erin

    Made this recipe and it worked great. Everyone was impressed and thought I’d bought it. It was easier than I expected. I did leave it to chill overnight after I added the chocolate mousse layer because it was taking a lot longer to set up than the peanut butter layer. I used the Hershey’s Special Dark cocoa powder as the other comments indicated and it still didn’t turn out as dark but it tasted fine. 

  12. Kaylene

    I tried to make this cake this afternoon. Although it looks awesome in the pictures, mine was a complete and total failure. I made it to the point of making the peanut butter mousse mixture, but it was so runny that it leaked past the brownie and out of my springform pan all over the counter and floor. I followed the instructions as they were written so I’m not sure what went wrong. I tried to at least salvage the brownies, but we’ll see how they are when I take them out of the fridge again. Hopefully anyone else who tries this will have better luck than I did!!! I will say that I’ve made other cake recipes from this blog (specifically the peanut butter cookie dough brownie layer cake ????) and they have all been great! Maybe I’ll get a different brand of peanut butter chips or whipping cream and try again. 

    1. Lindsay

      Hmm, it’s hard to say what happened. Did you use the full amount of powdered sugar in the whipped cream? It is used to stabilize it. I’d also make sure you didn’t add too much liquid to the peanut butter chips by accident. That will make a big difference.

  13. NICOLE

    Can’t wait to try this cake… one question.  My frostings is not dark like the photo.  Used 3 cups of whipping cream, 1/2 C powdered sugar, and 1/2 C of cocoa.  And it looks lighter then the choc. Mousse  layer.  Any suggestions?

    1. Lindsay

      It’s been a while since I made this cake, but it looks like I used the Hershey’s special dark cocoa. I’m guess you used regular unsweetened cocoa. Either works perfectly, the color is just a little darker with the dark cocoa.

  14. Ashley Nebel

    LOVED this cake. Made it for my assistant’s bridal shower at work and everyone kept asking me where I bought the cake. They couldn’t believe it was homemade. It was much easier to make than it looked! Thanks for the recipe…I have 3 more work showers for other co-workers and I will be using your site. 

  15. Fay

    Hi Lindsay – going to be out of town for a few days and need to make cake (s) several days in advance. How do you think your Peanut Butter Chocolate Mousse Cake would freeze? I have frozen cakes with stabilized whipped cream before and they were good but sometimes they sweat a bit while thawing. Thanks for your help and beautiful creation. ????

    1. Lindsay

      I haven’t frozen it before, but I would think the main concern would be sweating when thawing as you mentioned. I *think* it’d be ok.

  16. Laurel

    Hi Lindsay – absolutely love your site.  I’m currently making this cake…awaiting on the pb layer to set.  My question is this.  I’m using a 9″ springform pan.  The layers are so thick that the pb layer is almost to the top.  Yes, I have parchment paper around the edge about 1.5 inch above the top.  It seems to me that by the time I add the chocolate layer it’s going to be so high.  Will it work?  lol 

  17. Teri

    My 3 year old doesn’t really care for cake (strange, i know)! So, I went in search of a birthday cake recipe for non-cake eaters! I’ve never made a mousse before, and the steps were easy to follow, and the cake turned out exactly like the photo. It is a beautiful cake in real life, the separate layers, really are pretty! And, the taste and texture was absolutely delicious! I served it to 11 people, and EVERYONE went back for more (which is unheard of here)! I shared your recipe with 4 people, and everybody thought it was one of the best cakes, they had EVER had! Pretty high praise, in this house! Thank you so much for sharing, it really is a wonderful recipe!

Lindsay
About Lindsay

I'm a wife and mom to twin boys, a baby girl and a sweet black lab with a serious sweets addiction! Bring on the sugar!

Scripture I’m Loving

“Be joyful in hope, patient in affliction, faithful in prayer.” Romans 12:12