• Crush the cookies in a bowl.
• Melt the butter on medium heat, and integrate it with the cookie crumbs.
• Spoon the mixture equally into 12 small glasses.

For the filling:

• In a bowl beat the heavy cream until soft peaks form. Set aside. In another bowl, gently combine the mascarpone, sugar and banana flavoring. Fold in the whipped cream and stir gently to incorporate.
• Drizzle one tablespoon of the caramel sauce over the buttered crumbs in each of the 12 glasses.
• Fill half of each glass with the mascarpone filling, sprinkle some toasted walnuts on top, spread two banana slices and drizzle one tablespoon of the caramel sauce.
• Refill each glass with the mascarpone filling, and top it with the banana slices, chopped walnuts and caramel sauce.