For the mini magic cake Banoffee Pie, first preheat the oven to 160 degrees. Crumble the cookies. Cut the banana into thin slices. Melt the butter and set aside. Separate the egg whites and yolks.
For the batter, beat the egg yolks with the sugar until foamy. Add the melted butter, then the flour in two portions, then the milk. Beat the egg whites until stiff and fold into the mixture. The batter should be runny with the egg whites floating on top. Place a heaping teaspoon of cookie crumbs in each mold, top with 3-4 banana slices, and pour the batter over the top. Make sure that there is both liquid and egg white in each mold.
Bake the cookies for 25 minutes. The surface should be lightly golden brown. Remove from oven and let cool at room temperature for 1 hour, then refrigerate for another 2 hours.
To serve, carefully loosen the cake from the pans. In a mixing bowl, whip the whipped cream until stiff. Fold in 2 tablespoons of slightly warmed caramel. Pour into a piping bag fitted with a plain nozzle and refrigerate until just before serving.
Decorate the mini magic cakes with the caramel whipped cream. Warm the remaining caramel to make it more liquid and drizzle over the whipped cream. Garnish the Mini Magic Cake Banoffee Pie with banana slices and serve immediately.
The mini magic cakes Banoffee Pie can be stored in the refrigerator for 2 days.