For a truly decadent dessert, try your hand at this beautiful tart. Top with fresh raspberries and whipped cream for an even tastier treat.

Preparation

Crust:
Combine flour, sugar, ground hazelnuts and salt in a large mixing bowl. Add the butter and incorporate until dough is the consistency of lumpy cornmeal. Combine egg yolk with water and pour into a well in the dry ingredients. If dough is too crumbly, add ice water by the tablespoon.
Form dough into a disk, wrap in plastic and refrigerate for 30 minutes.

Once chilled, roll out pastry on a lightly floured surface into a 12-inch circle ¼ inch thick. Carefully roll dough onto rolling pin and transfer to 9-inch tart pan with removable bottom. Press the edges of the tart into the side of pan with your fingers, making sure it is even. Shave off excess dough from top. Use  any excess dough to patch holes or cracks. Refrigerate for 15 minutes.

Preheat oven to 350°F.
Place tart pan on a sheetpan. Line tart shell with foil and add pie weights or dry beans. Bake for 15-20 minutes, then remove foil, weights and beans. Using a pastry brush, lightly brush the crust with egg white. Return tart crust to oven and bake an additional 8 minutes, or until  light golden in color.
Set aside and lower oven temperature to 325°F.

Filling:
In a heavy saucepan over medium-low heat, bring cream and milk to a light simmer. Remove from heat and add the chocolate, vanilla and hazelnut liqueur, stirring until melted. Whisk in sugar and salt until incorporated. Beat eggs in a small bowl and add slowly to milk mixture to incorporate. Stir completely and pour into tart shell.   

Bake at 325° for 15-20 minutes until filling is set and top is shining. If there are bubbles or cracks on top, take out immediately—it is overcooked.

Let cool before serving.