Roughly chop the peanut butter cups. In a small saucepan over medium/low heat, melt 10 of the peanut butter cups.
Once melted, remove from the heat and beat it really well with a wire whisk - or use an electric mixer. Gently fold in the Cool Whip until combined.
Top with the remaining 4 Reese's cups (crushed). Serve with cookies, apples, or a spoon.