BEHIND THE APRON TIP: The key to successful buttercream is equal parts fat and sugar.
Now, what does that mean? If you are using one pound (one pound box of unsalted butter = 4 sticks), use one pound of confectioner's sugar. If doubling, for 2 dozen standard cupcakes, use one 2 pound bag of confectioner's sugar and two boxes of butter from the supermarket.
4 sticks unsalted butter, room temperature
1 pound bag of confectioner's sugar
2-4 tablespoons heavy whipping cream
2 tablespoons pure vanilla extract
Using the paddle attachment, beat butter for about three to four minutes on medium speed. Add sugar by the cup, mixing on a slow speed (so it doesn't jump out of the bowl). Increase the speed to high, combine vanilla and heavy whipping cream until you reach your desired texture.
(TIP: Add your food coloring before vanilla! This way, you can tweak your color without altering the quality of your frosting!)