Step 1

Preheat oven to 350 degrees and line cupcake pan with paper liners.

Step 2

For the cupcakes: Combine the cake mix, eggs, sour cream, milk, and vegetable oil in a large bowl until incorporated. Scrape sides of bowl and then beat on medium-high speed for 3 minutes.

Step 3

Fill cupcake liners halfway full and press one peanut butter cup into the center of each. Depending on your cupcake pan it could make about 16-20 cupcakes. Bake for 15-18 minutes or until done. Cool.

Step 4

For the Frosting: In a mixing bowl, cream butter and peanut butter until fluffy. Add the powdered sugar, vanilla, and milk and continue creaming until well blended. Blend on low speed until moistened. Beat at high speed until frosting is fluffy adding more milk if needed.

Step 5

Pipe frosting onto cupcakes. I used a wilton 2D tip. Garnish with the remaining peanut butter cups chopped.