In a bowl, combine 200 g crushed Biscoff cookies, melted butter, sugar, and salt. Press the mixture evenly into the base of a 9-inch springform pan until compact. Chill in the refrigerator.

Sprinkle 2 tsp gelatin powder over 3 tbsp cold water in a small bowl. Let it bloom for 5 minutes, then gently warm until fully dissolved and fluid.

In a medium bowl, beat together 250 g Biscoff spread, 100 g softened cream cheese, powdered sugar, and vanilla extract until smooth and glossy.

In a chilled bowl, whip 400 ml heavy cream to medium-stiff peaks.

Take a few tablespoons of the whipped cream and whisk them into the slightly cooled gelatin to temper it, then fold that mixture back into the whipped cream.

Gently fold one-third of the whipped cream into the Biscoff-cream cheese mixture, then fold in the remaining whipped cream in two additions.

Pour the mousse over the chilled crust, smoothing the top. Refrigerate the cake for at least 4–6 hours, preferably overnight.

Crumble 100 g Biscoff cookies over the top and add chocolate shavings or cocoa powder if desired.