• Preheat oven to 350⁰ F. Butter and lightly flour secret center cake pans, along with the wells-insert (this is the one where each cake will have a surprise). Set aside.
• Add ingredients to bowl and mix well,according to the instructions on the box of cake mix.  Pour two cups of the batter into the cake pan with the wells-insert.  Pour the rest of the batter into the other pan.  Bake for20-24 minutes, or until cake tester inserted into canter of cake comes out clean.
• Remove from oven. Cool 10 minutes, then remove cakes from pan and let cool completely.

For the Frosting:

• Mix together butter and peanut butter until combined. 
• Slowly add in powdered sugar, mixing on low speed until fully incorporated. 
• Add in vanilla and salt, mix well.  Finally, add in milk, and give a finally mixing.
• Once cooled, remove well-insert from cake, and slice crown to level if necessary.
• Use the Easy Accent Decorator to pipe frosting around the wells for the bottom layer, and in the center of that cake. 
• Fill the wells with Reese’s Pieces, then other layer of cake on top. Frost the rest of the cake, decorate top with chopped dark chocolate, if desired.
• Chill cake for at least one hour before slicing and serving.