Whip the butter with the sugar, add the eggs one at a time and finally the milk.
Finish with wheat starch, flour and baking powder, preaviously sieved. Pour the dough into a well-buttered 20 cm tart mold and bake at 170°C for 30 minutes.
Prepare the hot chocolate by pouring Cioccodelizia Classica Babbi and the milk into a saucepan and bringing it to the boil, stirring; once a good consistency has been reached, allow the cake to cool and fill the cake.
Whip the fresh cream, sweetened to taste with powdered sugar and decorate the cake with some swirls; put some red coloring inside the sac-a-poche to get a marbled effect.