1. Prepare three 8 inch cake pans with parchment paper circles in the bottom and grease the sides. Preheat oven to 300°F (148°C).
2. Add all dry ingredients to a large bowl and combine.
3. Add eggs, milk, vegetable oil and Irish cream to the dry ingredients and mix well.
4. Combine the water and vanilla extract and slowly pour into the batter. Mix well.
5. Divide the batter evenly between the cakes pans and bake for about 32-34 minutes, or until a toothpick comes out with a few crumbs.
6. Remove the cakes from the oven and allow to cool for about 10 minutes, then remove to cooling racks to cool completely.
7. White the cake cools, make the frosting. Beat the butter and shortening together until smooth.
8. Slowly add about 1/2 of the powdered sugar, mixing until smooth between each addition of powdered sugar.
9. Add 4 tablespoons of Baileys to the frosting and mix until smooth.
10. Slowly add the remaining powdered sugar, mixing until smooth between each addition of powdered sugar.
11. Add additional Baileys to the frosting, as needed to get a smooth consistency.
12. To put the cake together, use a large serrated knife to remove the domes from the tops of the cake layers so that they are flat. See my tips on how to level a cake and how to stack a cake.
13. Place the first layer of cake on your serving plate or on a cardboard cake circle.
14. Spread 1 cup (240g) of frosting into an even layer.
15. Add the second layer of cake, then another cup (240g) of frosting.
16. Top the cake with the third layer of cake.
17. Frost the outside of the cake with the remaining frosting. For help getting a smooth finish, refer to my tutorial on how to frost a smooth cake with buttercream.
18. Set the cake aside and make the chocolate ganache (see my tips on making chocolate ganache). Add the chocolate chips to a metal or glass bowl.
19. Microwave the heavy whipping cream until boiling, then pour over the chocolate chips. Cover the bowl with clear wrap for about 5 minutes.
20. Whisk chocolate until smooth.
21. Use a spoon to drizzle the chocolate ganache down the sides of the cake. See my tips on making a chocolate drip cake.
22. Pipe dollops of frosting around the border of the cake. I used Ateco tip 808.
23. Spread the remaining ganache into the center the of the piped border.
24. You can store the cake in an air tight container at room temperature for up to 24 hours. If setting out for longer than 24 hours, you may want to refrigerate the cake because of the chocolate ganache. Cake is best served at room temperature. Cake is best for 2-3 days.