Crumble the biscuits coarsely. Melt the butter with the liquid cream and add the chocolate spread.
Stir until everything is homogenized. Take off the stove and wait for the mixture to cool but not to the point where it hardens.
Mix the mascarpone in it, next stir in the walnuts and raisins. If the mixture seems too thick, you can add a little warm milk to it.
Sprinkle the biscuits with a little milk and carefully mix them with the warm chocolate mixture.
Distribute everything into an oven dish and smooth out. Let it sit overnight and serve the next day.