Finely crush the chocolate crème sandwich cookies in a food processor until they reach a fine crumb texture, about 30 seconds. In a mixing bowl, combine the cookie crumbs with melted unsalted butter, ensuring they’re well-coated. Evenly press this mixture into the bottom of individual serving glasses, creating a firm crust. Refrigerate the glasses for at least 15 minutes to help the crust set properly.

In a large mixing bowl, beat together softened mascarpone cheese, chocolate hazelnut spread, powdered sugar, and vanilla extract using an electric mixer on medium speed until the mixture is smooth and creamy, approximately 2-3 minutes. In a separate chilled bowl, whip the heavy cream to soft peaks, which takes about 3-5 minutes. Gently fold the whipped cream into the mascarpone mixture in thirds.

Once the crusts are set, spoon the mascarpone filling over the chilled cookie crusts, dividing it evenly among the glasses. Use a spatula to smooth the top. Cover with plastic wrap and refrigerate for at least 2 hours, or overnight.

When ready to serve, remove from the refrigerator and garnish with whipped cream and optional toppings like chocolate curls or toasted nuts. Serve chilled.