Remove tops from 16 Oreos, keeping the cream sides up. You can freeze the 16 tops to use later for an chocolate cookie pie crust.
Set Oreo half on your work surface (cream side up).
Top it with a peanut butter cup.
Set another Oreo half on top of that (cream side down) and gently press together.
Repeat until you have 8 cookie sandwiches.
Melt the chocolate with the butter in the microwave in 15-30 second intervals until smooth.
Use a fork to dip each sandwich in melted chocolate until completely covered (I'm not sure how people do this without being up to your elbows in chocolate...not that that's a bad thing).
Gently shake off the dripping chocolate then set each cookie on cooling rack.
Sprinkle with colorful sprinkles.
Refrigerate untl the chocolate is set.