Beat butter and Nutella until combined. (about 1 minute)
Add 1 cup of the icing sugar and beat until combined.
Add remaining cup of icing sugar and beat until fluffy. (about 2 minutes)
Add vanilla and continue to beat until combined.
If you want swirls of Nutella you can add an additional spoonful of Nutella and give it a quick stir.
For a marbled effect remove 2 separate ¼ cup portions of the finished frosting. Mix 1 teaspoon of Nutella into the first ¼ cup portion and 2 teaspoon of Nutella to the second ¼ cup portion. Alternate adding the three different icings on to the cake and pat with a spatula. Drizzle with more Nutella.
