Toasted Hazelnut Crust:

1. Toast the hazelnut flour: Place hazelnut flour in a medium skillet over medium-low heat. Cook, stirring often, until golden-brown and fragrant (about 5 minutes). Immediately remove from heat and allow to cool completely before using (20-30 minutes). Meanwhile, preheat oven to 350ºF. 
2. Make the crust: Combine cooled hazelnut meal with the remaining dry ingredients in a food processor fitted with the steel blade attachment, and pulse to combine. Add the butter and pulse in until pea-sized. Add the egg and vanilla extract and pulse just until the ingredients are evenly moistened and start to clump together, adding the ice water if needed.
3. Bake: Transfer mixture to a 9.5” round tart pan and press evenly into the bottom and sides. Trim excess dough along the top border to form a clean edge. Use a fork to prick the bottom of the crust multiple times. Transfer to preheated oven and bake for 10-13 minutes, until just starting to turn golden. Allow to cool completely (about 1 hour) before making ganache filling.

Nutella Ganache Filling:

1. Make the ganache: Add cream to a medium, microwave-safe bowl and microwave until just beginning to boil (about 60-90 seconds). Submerge chocolate into cream and let sit for 5 minutes. Stir until smooth. Whisk in the Nutella until smoothly incorporated. Pour filling into the prepared crust and chill in the refrigerator until set (about 1 hour).

Whipped Cream & Garnish

1. Make the whipped cream: Using a bowl and electric mixer, beat the cream on medium speed until starting to thicken. Add the confectioner’s sugar and vanilla extract and continue to beat just until stiff peaks form.
2. Finish and garnish: Use an offset spatula to spread the whipped cream over the top of the tart. Garnish with toasted hazelnuts. Chill until ready to serve.