Chocolate Peanut Butter Snack Cake

A thick layer of moist chocolate cake topped with a rich, creamy peanut butter mousse. It’s everything you want out of a chocolate + peanut butter combo. This chocolate peanut butter snack cake is about to be your new favorite dessert!

1 hour 30 minutes
For the Chocolate Cake
  • ½ cup (113g) unsalted butter
  • 1 ⅓ cup (285g) granulated sugar
  • ½ cup (56g) cocoa powder
  • 2 large eggs
  • 1 teaspoon vanilla extract
  • 1 ½ cups cake flour
  • 1 teaspoon baking soda
  • ½ teaspoon baking powder
  • ¼ teaspoon salt
  • 1 cup (204g) water
For the Peanut Butter Mousse
  • ¾ cup (190g) creamy peanut butter
  • ¼ cup (57g) unsalted butter
  • ½ cup (60g) powdered sugar
  • ¾ cup (6oz / 170g) heavy cream
For the Topping
  • 8-10 Reese’s Miniature Cups, chopped (optional)
  1. Chocolate Cake: Preheat oven to 325°F. Lightly grease an 8” x 8” square pan with cooking spray. Line with parchment paper to create a sling, with an overhang on all four sides.
  2. In the bowl of a stand mixer fitted with a paddle attachment, cream the butter and sugar until fluffy and light in color, about 5 minutes.
  3. Add the eggs one at a time and vanilla, combining well after each addition. Scrape the bowl then add the cocoa powder. Start on the lowest speed and increase to medium speed until well combined. Scrape the bowl again.
  4. Sift together the cake flour, baking soda, baking powder, and salt. Alternate adding the flour mixture and water, starting and ending with the flour. Mix until just combined after each addition and scrape down the bowl a few times during the process.
  5. Pour batter into the prepared pan and smooth out the top. Bake for 45-50 minutes, or until the cake springs back to the touch (or a toothpick comes out clean). 
  6. Allow the cake to cool completely before frosting.
  7. Peanut Butter Mousse: In a large mixing bowl, combine the peanut butter, and butter with an electric mixer until well combined and smooth with no lumps remaining. Add the powdered sugar and mix just until fully combined.
  8. In a separate bowl, whip the heavy cream to soft peaks then mix into the peanut butter mixture until thick and smooth. 
  9. Spread the peanut butter mousse on the top of the cooled cake, using a tapered spatula and pushing the frosting just to the edges and corners. 
  10. Sprinkle the chopped mini peanut butter cups on top, if desired. Slice the cake up and enjoy!

  • I recommend using a thick, conventional peanut butter like Skippy or Jif. A natural variety won’t quite work the same in this recipe.

  • Store the cake in an airtight container in the fridge for up to 3 days.