Tart dough: Pour the flour into a bowl over which add the diced butter, salt and sugar. Stir until the dough has the texture of a breadcrumbs. Add the egg over the composition and add it. Add little by little from the cold water until a homogeneous dough is formed. Remove the dough and let it rest in a cold plastic wrap for about 15 minutes. After the expiration of the 15 minutes, spread the dough with a rolling pin. Take a tart shape and spread it carefully. Remove the edges and let it cool again for 20-25 minutes to harden well. The hardened dough is impregnated from place to place with a fork. Place a baking sheet and ceramic balls for the tart over the dough so as not to increase the dough too much. Bake the tart for about 20 minutes in the preheated oven at 200 degrees. Leave the crust to cool.
Filling: Put the milk in a saucepan on the fire, put the cream, whipped cream, sugar and butter over it and let it boil. Remove from the heat and pour over the broken chocolate pieces in another bowl. Let the composition stand for a few minutes then mix in it until it is homogenous. Add eggs one at a time. Pour the chocolate filling into the baked and cooled crust. Place the tart in the oven again in the preheated oven at 175 degrees for 25 minutes to set. Leave it in the fridge overnight and the next day it can be cut.