Preheat the Oven: Preheat your oven to 350°F (175°C). Line a muffin tin with cupcake liners.
Dry Ingredients: In a large bowl, whisk together the flour, sugar, cocoa powder, baking powder, baking soda, and salt.
Wet Ingredients: In another bowl, beat the eggs, milk, vegetable oil, and vanilla extract until well combined.
Combine: Gradually add the wet ingredients to the dry ingredients, mixing until just combined. Stir in the boiling water until the batter is smooth. Finally, fold in the 1/2 cup of Nutella.
Fill the Cupcake Liners: Fill each cupcake liner about 2/3 full with batter. If you want a Nutella center, fill each liner 1/3 full, add a teaspoon of Nutella, then cover with more batter.
Bake: Bake for 18-22 minutes, or until a toothpick inserted into the center comes out clean. Allow the cupcakes to cool in the pan for a few minutes before transferring them to a wire rack to cool completely.
Making the Nutella Frosting:
Beat the Butter: In a large bowl, beat the softened butter until creamy and lightened in color.
Add Nutella: Mix in the Nutella until well combined.
Powdered Sugar: Gradually add the powdered sugar, one cup at a time, beating well after each addition. Add heavy cream as needed to reach your desired consistency.
Flavor: Mix in the vanilla extract and a pinch of salt.
Frost the Cupcakes: Once the cupcakes are completely cool, frost them with the Nutella frosting using a piping bag or a knife.
