Briefly dip each biscuit in coffee or milk. Do not soak them.
Arrange the dipped biscuits in a single layer over the bottom of the pan until fully covered.
In one bowl, mix the mascarpone and powdered sugar until smooth and creamy.
In a second bowl, whip the cold whipping cream with 2 tablespoons caramel cream until firm peaks form.
Using a spatula, gently fold the whipped cream mixture into the mascarpone mixture until evenly combined.
Divide the filling into 2 equal parts.
Spread half of the filling evenly over the biscuit base and smooth the top.
Dip the remaining biscuits briefly in coffee or milk and arrange them over the first cream layer in an even layer.
Spread the remaining filling over the second biscuit layer and smooth the top evenly.
Cover and refrigerate for 2 to 3 hours so the cake can set.
Gently warm the 3 tablespoons caramel cream over steam or on very low heat.
Add 1 to 2 tablespoons milk only if needed, until the caramel becomes pourable and smooth.
Let it cool slightly so it is warm, not hot.
Pour it over the chilled cake and spread gently if needed.
Return the cake to the fridge for 1 more hour to set the topping.
Decorate as desired with crushed biscuits, whipped cream, extra caramel, caramel bits, or a little chocolate shaving.
Slice and serve chilled.