Make the cupcakes

1. Preheat oven to 350°F (176°C) and prepare a cupcake pan with cupcake liners.
2. Combine the flour, baking powder, baking soda and salt in a medium sized bowl and set aside.
3. In a large bowl, whisk the melted butter, sugar and vanilla extract together until well combined.
4. Add the eggs and whisk together until well combined.
5. Add the sour cream and Nutella and whisk together until well combined. Now, add the milk and whisk together until well combined.
6. Add the dry ingredients and whisk together until combined, but do not over mix.
7. Fill the cupcake liners a little more than 1/2 full (51g) and bake for 16-20 minutes or until a toothpick inserted into the center comes out clean and the edges are just lightly golden.
8. Remove cupcakes from the oven and place on a cooling rack to cool.

Make the buttercream

1. While the cupcakes cool, make the frosting. Add the butter and Nutella to a large mixer bowl and mix until well combined and smooth.
2. Add about half of the powdered sugar and mix until well combined and smooth.
3. Add 2 tablespoons of cream and mix until well combined and smooth.
4. Add the remaining powdered sugar and mix until well combined and smooth.
5. Add the remaining cream as needed and mix until smooth.

Put cupcakes together

1. When the cupcakes have cooled, use a cupcake corer to remove the centers from the cupcakes.
2. Use the additional Nutella to fill the cupcakes, then pipe the buttercream on top of the cupcakes. I used Ateco tip 847.
3. Finish off each cupcake with half of a Ferrero Rocher candy, if desired. I also sprinkled some finely chopped hazelnuts on top.