Preheat oven to 400 degrees F.

Butter the bottom and sides of an 11-inch tart pan with removable bottom; set aside.

Place hazelnuts on a baking sheet and toast for 5 minutes. Remove from oven and cool. Place cooled nuts in food processor. Add 2 tablespoons of the flour and pulse until finely ground. Place the ground nuts, remaining flour, and salt into a large bowl and combine. Combine the confectioners' sugar, brown sugar, and egg yolks. Using a wooden spoon combine the sugars and yolks until sugars dissolve. Add the softened butter and begin to add the flour and nut mixture. When it is well combined, form a ball and knead the dough. Flatten the dough into a disk and wrap it in waxed paper. Refrigerate for 1 hour.

Lightly flour the top and bottom of the dough and roll out between 2 sheets of parchment paper. Turn the dough out into the tart shell and press gently to line the sides. Trim the excess from the edge. Freeze the tart shell for 10 minutes.

Line the inside of the tart shell with aluminum foil. Place 3 cups of dried beans on top of the foil and place the tart shell on the baking sheet. Bake for 15 minutes. Remove the tart shell from the oven. Cool on a rack leaving beans inside. When cool, remove the foil and beans. Reduce temperature to 325 degrees F.

Place milk in a saucepan. Boil and steep the mint and milk for 10 minutes stirring constantly. Drain and discard the fresh mint. Pour hot milk over chopped chocolate. Let stand for 20 seconds, and then whisk gently. Whisk in the vanilla extract.

In a large bowl, whisk eggs, yolks, and sugar until blended. Slowly whisk in the chocolate mixture. Using a fine mesh sieve, strain the filling into the cooled pie shell. Bake for 20 minutes or until set. Remove the tart from the oven and cool on a rack. When cool, place in refrigerator until ready to serve.