1 1/2 cups butter, at room temperature (3 sticks)*
4 1/2 cups powdered sugar
3 Tbsp heavy cream
1 1/2 tsp vanilla extract (use clear if desired)
In the bowl of an electric stand mixer, using the paddle or whisk attachment whip butter on medium high speed (if using whisk attachment whip on high speed) until nearly white and very fluffy, about 7 - 8 minutes, frequently scrapping down the sides of the bowl. Add in powdered sugar, heavy cream and vanilla extract and mix on low speed until blended, then increase speed to medium and beat until very light and fluffy, about 5 - 6 minutes, frequently scraping down the sides of the bowl. Immediately spread over cooled cake or cupcakes.
Note: if you want an alternate flavor of frosting, coconut or almond extract would be a great substitute for the vanilla extract, just add it to taste.
*I use half salted butter and half unsalted butter (3/4 cup of each)
Recipe Source: Cooking Classy