Vanilla: For a vanilla buttercream frosting, I like to add an additional teaspoon of vanilla extract to amp up the vanilla flavor.
Chocolate: Sift 1/2 cup (40 grams) of unsweetened cocoa powder and mix it into the frosting base until well combined. Add 1 to 2 extra tablespoons of heavy cream if needed for a smoother, creamier frosting. For a sweeter frosting, mix in an additional 1/2 to 1 cup (60 to 120 grams) of powdered sugar.
Caramel: Mix in 1/3 to 1/2 cup of homemade or store-bought caramel sauce. For a salted caramel frosting, you can use salted caramel and omit the salt in the recipe.
Strawberry: Add a 28 g bag of freeze dried strawberries to a blender or food processor and process until the berries are crushed into a fine powder. Mix the freeze dried strawberry powder into the frosting base until well combined.