Monster Cookie Cake

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This Monster Cookie Cake is full of M&Ms, chocolate chips, peanut butter and oats for a cookie cake that’s fun, chewy and delicious! It’s easy to make and perfect for parties!

Monster Cookie Cake

Monster Cookie Cake

This past weekend I went to see the Boyz II Men, Paula Abdul and New Kids on the Block concert with some friends. It was a ton of fun, but totally surprised me in several ways. I was primarily there to see Boyz II Men and Paula, who I listened to a ton as a kid and still listen to regularly. I went with one of the same friends to an En Vogue and Boyz II Men concert a few years ago and that was my favorite concert ever. I LOVE both of those groups, so we were surprised when we were a little underwhelmed by Boyz II Men in this concert.

Then there was Paula. She can still definitely bust a move, but even she wasn’t as exciting as I was hoping for.

Surprisingly, despite knowing only one of their songs and not really listening to them much at all as a kid, NKOTB was the best part of the show! The show was clearly built around them and it was a party. They were so darn fun to watch, had a great sense of humor and I totally fell in love with Donnie Wahlberg. He seems like the most genuinely nice dude. I kind of want to be his best friend.

So clearly NKOTB can rock a concert. I would still go to a Boyz II Men concert any day over another, but NKOTB totally rocked it and we had a great time.

Best Monster Cookie Cake
Decorated Monster Cookie Cake

This cookie cake also rocks the house and is game for a good time. 😉 It’s festive, colorful and full of chocolate and peanut butter – what’s not to love?!

My family has been eating cookie cakes for as long as I can remember. My dad was basically the cookie monster in the house and has never had anything but a cookie cake for his birthday. I’ve made several versions over the years (including a Reeses Peanut Butter Cookie Cake, Funfetti Cookie Cake, Triple Chocolate Cookie Cake), but it’s been a while since I shared a new one. While my dad’s a fan of the classic Chocolate Chip Cookie Cake, he also is a fan of oatmeal cookies like this Oatmeal Raisin Cookie Cake. And as far as making a “cake” goes, this one is about as easy as it gets.

Tips for Making Monster Cookie Cake

Like with most cookies, you’ll start with by creaming the butter and sugar. In this case, you’ll also have the peanut butter in there. Then you’ve got your usual suspects – eggs, vanilla, dry ingredients. And who could forget the tasty mix-ins? With the peanut butter and oats, they might not stick to the dough super well, but they mix fine and it’s easy enough to press them into the dough once it’s in the cake pan.

Bake it just until the edges are turning golden, no more. You don’t want to over bake it and end up with a dry cookie.

Frost it with some chocolate frosting, add some crushed up M&Ms and you’ve got yourself one fun and fancy cookie cake! It’s great for a celebration, but also an easy way to enjoy cookies without having to make all the individual cookies. Score!

Monster Cookie Cake sliced overhead view
Favorite Monster Cookie Cake with M&M's

Watch How To Make It

Read Transcript

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overhead image of Monster Cookie Cake slices

Monster Cookie Cake

  • Prep Time: 10 minutes
  • Cook Time: 16 minutes
  • Total Time: 26 minutes
  • Yield: 12-14 Slices
  • Category: Dessert
  • Method: Oven
  • Cuisine: American


This Monster Cookie Cake is full of M&Ms, chocolate chips, peanut butter and oats for a cookie cake that’s fun, chewy and delicious! It’s easy to make and perfect for parties!



  • 1/4 cup (56g) unsalted butter
  • 6 tbsp (105g) peanut butter
  • 1/2 cup (72g) brown sugar
  • 3 tbsp (39g) sugar
  • 1 egg
  • 1 tsp vanilla extract
  • 1 cup (130g) flour
  • 3/4 tsp baking soda
  • 1/4 tsp baking powder
  • 1/4 tsp salt
  • 1 1/4 cups (110g) quick cook oats
  • 3/4 cup (150g) M&Ms
  • 1/2 cup (85g) chocolate chips


  • 1/2 cup butter
  • 1 3/4 cup (201g) powdered sugar
  • 1/4 cup (29g) natural unsweetened cocoa powder
  • 1/2 tsp vanilla extract
  • 12 tbsp water or milk


1. To make the cookie bottom, preheat the oven to 350°F (176°C). Place parchment paper in the bottom of a 9 inch cake pan and grease the sides.
2. Cream the butter, peanut butter and sugars together until light and fluffy, about 3-4 minutes.
3. Mix in the egg and vanilla extract until combined.
4. In a separate bowl, combine the flour, baking soda, baking powder and salt.
5. Add the dry ingredients to the butter mixture and mix until well combined.
6. Stir in the oats. The cookie dough will be thick.
7. Stir in the M&MS and chocolate chips. They may not stick to the dough completely, but will be fine once in the cake pan.
8. Pour the the dough in the prepared cake pan and evenly press into the bottom. Press some of the mix-ins that wouldn’t stick to the dough into the cake pan.
9. Bake for 16-18 minutes or until the edges are slightly golden.
10. Remove from oven and allow to cool completely in the pan.
11. To make the frosting, beat the butter until smooth.
10. Slowly add about half of the powdered sugar and mix until well combined.
11. Add the cocoa, vanilla extract, 1 tablespoon of water and the remaining powdered sugar and mix until smooth.
12. Add more water, if needed to get the right consistency.
13. Pipe the frosting onto the edges of the cookie cake, then store in an airtight container until ready to serve.


  • Serving Size: 1 Slice
  • Calories: 279
  • Sugar: 24.7 g
  • Sodium: 213.3 mg
  • Fat: 12.7 g
  • Carbohydrates: 38.7 g
  • Protein: 4.9 g
  • Cholesterol: 22.1 mg



Best Monster Cookie Cake recipe
Monster Cookie Cake - full of M&Ms, chocolate chips, oats and peanut butter!
About Lindsay

I'm a wife and a mom to twin boys and a baby girl! And I've got a serious sweets addiction! Bring on the treats!

Scripture I’m Loving

“Come to me, all you who are weary and burdened, and I will give you rest. Take my yoke upon you and learn from me, for I am gentle and humble in heart, and you will find rest for your souls.” Matthew 11:28-29