A versatile white frosting that can be flavored to suit your recipe.

2 sticks unsalted butter, room temperature
3 cups confectioners sugar, divided
1 teaspoon vanilla extract or flavor of your choice
2 tbsp milk or rice milk

Cream together butter and 1 cup of sugar on low-speed. Beat in remaining two cups of sugar on low-speed, scraping the bowl as you work.
Add vanilla and milk, beating on low-speed until ingredients are blended and frosting is smooth.