Dessert: Peanut Butter Cup Bliss Sheet Cake

Recipe by Sally Quinn The best way to please a party? A sheet cake topped with peanut butter frosting and Reese's.

Ingredients

2 c. all-purpose flour
1 tsp. baking soda
1/4 tsp. salt
1 c. unsalted butter
1 c. water
1/2 c. Unsweetened cocoa powder
2 large eggs, at room temperature
1 c. sugar
1/2 c. packed light brown sugar
2 tsp. vanilla extract
1/2 c. buttermilk, at room temperature

Instructions

Make cake: Preheat oven to 350 degrees F. Generously grease a 12-x-17" half sheet/jelly roll pan. Set aside.
Heat butter, water, and cocoa powder together in a large saucepan over medium heat. Whisk constantly until butter has melted and everything is smooth and combined. Set aside. In a large bowl, whisk together flour, baking soda, and salt. Pour warm chocolate/butter mixture on top, then slowly whisk together until combined.
Whisk eggs, granulated sugar, and brown sugar together in a medium bowl. (The mixture will be thick.) Whisk in vanilla until combined, then pour into chocolate batter and whisk until combined. Finally, whisk in buttermilk. Pour chocolate batter into prepared sheet pan.
Bake 15 to 20 minutes. Use a toothpick to test for doneness: Stick it into the cake. If the toothpick comes out clean, the cake is done. If not, continue baking. Remove cake from oven and set pan on a wire rack. Let cake cool completely in pan before frosting. (The refrigerator helps speed things up, if you have room for the large pan!)
Make frosting: Using a handheld or stand mixer fitted with a whisk attachment, beat softened butter and peanut butter together on medium-high speed for 2 minutes until completely smooth and creamy. Add confectioners' sugar, cream, vanilla extract, and salt. Beat on low speed about 20 seconds, then gradually increase to high speed. Beat on high 1 minute until combined and frosting is fluffy. Taste; add more salt if needed. To thicken, add more confectioners' sugar; to thin, add more cream.
Spread frosting all over cooled cake, then drizzle with melted peanut butter and top with chopped peanut butter cups and mini chocolate chips. Slice and serve. Cover leftovers tightly and store in the refrigerator for up to 5 days. It's so good cold!
Make ahead tip: Cake can be made 1 day in advance, covered tightly at room temperature, and then frosted before serving. Frosting can also be made 1 day ahead of time; cover tightly and keep in the refrigerator.