Preheat oven to 350°. Beat butter until fluffy, then add cake mix, eggs and buttermilk. Beat together until fully mixed. Fill ¾ of cupcake liners with cake mix. Bake 20-25 minutes. Allow to cool.
Beat softened butter until fluffy. Mix in softened cream cheese, confectioners’ sugar, vanilla extract, and beat until thoroughly mixed. Cool for 15 minutes and until the cupcakes are cool, then spread the frosting and serve!