Pre-bake a short pastry in a round shape (tart pan or springform pan) for approx. 10-15 minutes.
Bring the cream with the butter to the boil, remove from the heat and pour in the dark chocolate. Stir until the chocolate is completely (!) Dissolved. Whisk the egg with the milk and add to the chocolate mass. Put the mixture on the dough base and bake at about 160 degrees for about 10-13 minutes. Since every oven bakes differently, I can only say as a tip that the mass has to be hardened.