Ahh, Reese's Frosting: it's like peanut butter cups in frosting form. Absolutely fabulous on brownies, cupcakes, toast and straight up spoons! Heavenly goodness :)
Stir butter, Reese's spread and powdered sugar together to combine. It will be pretty dry for a few good seconds but after that should look more brown than white.
Add in vanilla and enough milk to create a frosting consistency. Scrape sides and mix again until completely smooth. Stir in chopped Reese's Peanut Butter Cups and spread on anything your little heart desires.