For the cupcakes: Preheat the oven to 350 degrees F. Line 2 muffin pans with 24 cupcake liners.
Sift together the flour, baking powder, baking soda, and salt in a medium bowl.
Whisk the hazelnut liquor and cocoa powder together until combined.
In the bowl of a stand mixer with a paddle attachment, cream the butter and sugars together on medium-high speed until light and fluffy, 2 to 3 minutes. Add the eggs, 1 at a time, until each has been incorporated. Add the buttermilk and vanilla extract and mix until fully combined. Turn the mixer to low, and add the flour and cocoa mixture, alternating between the 2, beginning and ending with the flour. Mix until just combined and no streaks remain. Set aside while you prepare the filling.
For the filling: In the bowl of a food processor, grind the hazelnuts until they reach a very fine sand consistency. Add the hazelnut spread and process until the mixture begins to clump. Add the hazelnut liquor 1 tablespoon at a time, or until the mixture is able to ball easily in your hand.
With your hands, form the paste into balls about the size of a very large cherry. Roll the balls lightly in the flour to absorb any excess liquid.
To assemble: Fill the cupcake liners about 1/4 of the way full with the cupcake batter. Place 1 ball of filling in each liner, and then cover the filling with the remaining batter so each cupcake is about 3/4 of the way full.
Bake until a toothpick inserted into the center comes out clean, 20 minutes. Cool the cupcakes completely.
Dip each cupcake top into the Chocolate Ganache, forming an even layer, and allow to cool.
In a heat-proof bowl, microwave the heavy cream on high for 1 to 2 minutes. The cream should be very hot to the touch.
While the cream is being heated, place the chocolate chips and espresso powder in a medium heat-proof bowl. Once the cream is ready, pour it on top of the chocolate chips and whisk until the chocolate is completely melted and the mixture has thickened. Whisk in the vegetable oil for extra shine.
If mixture begins to harden or if the cream is not hot enough, place the bowl over a pot of simmering water.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Jenny Harrison and Mariel Williams, Cupcake Wars, 2010