For the cupcakes:

Preheat oven to 350°.

In the bowl of a stand mixer, combine butter and sugar together until completely incorporated.

Melt the chocolate and let cool for a minute or so, then add to mixer on low to combine.

Add the eggs and egg yolks until combined.

Mix in the vanilla, oil and sour cream.

Sift together the cocoa, flour, baking soda, and salt in a separate bowl and then add into the mixture.

Pour in the cooled coffee and mix until everything is combined.

Fill your cupcake liners and set aside to prepare the chocolate ganache.

For the Chocolate Ganache:

Heat chocolate, sugar and heavy cream in microwave for about 30 seconds.

Mix together with a spoon until combined.

Let it cool in the refrigerator for no longer than 30 mins (will start to harden)

Then, go back to your cupcake batter in the cupcake tin.

Place a dollop of ganache into the top center of each cupcake.

Bake for about 20 minutes or until toothpick comes out clean.

For the Nutella Buttercream:

Using the whisk attachment, cream together the butter and nutella.

Add in the sugar and salt and mix on low speed until incorporated.

Add in the heavy cream and vanilla on low speed.

Whisk the frosting on medium-high speed until light and fluffy.

Frost cupcakes when they are completely cool or else frosting will melt!