Preheat oven to 350°.
To make the crust, toast the hazelnuts. Place nuts in between two paper towels and roll to remove skin. Pulse in a food processor until fine. Combine with remaining crust ingredients until you get the consistency of wet sand. Place crust in a tart pan, making sure to cover the sides as well. Blind bake in the preheated oven (place aluminum foil and dried beans on top) until the crust is hard. Let cool before adding filling.
To make the filling, heat the heavy cream. In a separate bowl, combine cream with chocolate until the chips have melted. Add the rest of the filling ingredients, adding the eggs last after the mixture has had time to cool. When the crust has cooled, fill it with filling and bake until firm.
To make the glaze, heat the heavy cream and mix with chocolate chips until melted. Add the rest of the glaze ingredients. Pour glaze over the cooled tart and rotate tart until the top is completely covered. Refrigerate until completely cool, then serve with ice cream if desired.