Preheat oven to 325º F and fill two muffin tins with cupcake liners.

Add flour, sugar, cocoa, baking powder, baking soda, and salt to a large bowl. Whisk through to combine well.

Add milk, vegetable oil, eggs, and vanilla to flour mixture and mix together until well combined (you can also use a stand mixer and mix on medium). Carefully add boiling water to the cake batter. Beat quickly for about 1 minute to add air to the batter (you can also use a stand mixer and mix on high).

Evenly distribute cake batter so each cupcake liner is about 3/4ths full.

Place in the oven and bake 13-19 minutes or until a toothpick inserted in the center comes out clean.

Remove from the oven and allow the cupcakes to cool completely.

Beat together butter and shortening until smooth, then add Nutella and mix until combined.

Slowly add 4 cups of powdered sugar and mix until smooth.

Add 2-3 tbsp of milk and mix until smooth.

Add the fifth cup of powdered sugar and mix until smooth. If more milk is needed, add a teaspoon at a time to reach your desired consistency (it should be stiff but light).

Using a small paring knife, cut small holes out of the middle of each cupcake, being careful not to reach the bottom of the cupcake. Place removed pieces of cupcake to the side.

Fill a pastry bag fitted with a round tip (or a Ziploc bag with the tip cut off) with the Nutella filling.

Slowly fill each cupcake with the Nutella filling up to the very top of the cupcake. Set extras aside.

Place chocolate chips in a metal bowl.

Heat heavy whipping cream in a small saucepan over medium-high heat until it just starts to boil. Remove from heat and pour over chocolate chips. Do not stir, and let sit for 5 minutes.

Stir chocolate and cream until smooth, and let sit an additional 15-20 minutes, until slightly thickened.

Spoon chocolate ganache over the top of each cupcake. Top each cupcake with remaining icing (if using a pastry bag, a medium star tip will work great) and sprinkles, if desired. Enjoy!