Step 1

Preheat oven to 350 degrees F. Line a cupcake tin with paper liners.

Step 2

In a large bowl whisk flour, sugar, baking soda, baking powder, and salt together.

Step 3

Stir in butter, Nutella, egg whites, milk, sour cream, and vanilla until smooth.

Step 4

Fill cupcake liners around 3/4 of the way full. Bake for 19-21 minutes or until a toothpick inserted in the center comes out clean.

Step 5

Cool in pan for 3-4 minutes. Remove to wire rack to cool completely.

Step 6

Cream butter until light and fluffy. Stir in Nutella, vanilla, and salt.

Step 7

Gradually add powdered sugar a little a time until just combined. Add milk as needed to reach your desired consistency.

Step 8

Pipe or spread Nutella buttercream onto cupcakes.

Step 9

If desired: heat Nutella in the microwave for 30-60 seconds. Drizzle over cupcakes. Top with strawberry slices.