Unwrap and cut 2 Milky Way bars into chunks. Place in a microwave safe bowl with butter. Cook in microwave in 30 second intervals, stirring in between until melted and smooth.

Pour melted butter and candy bar mixture into a mixer bowl and add 1 cup of powdered sugar and 1 tablespoon of milk. Beat together at medium speed, slowly adding more powdered sugar and milk alternately until desired consistency.

Unwrap and chop remaining Milky Way bar into small pieces. Fold into the icing.

Spread icing over 12 baked and cooled cupcakes and serve immediately.