Preparation Steps

• Line the bottom and sides of a 9-inch springform pan with parchment paper. Reserve a few tablespoons of the crushed Speculoos for garnish.
• Make the crust: combine the crushed Speculoos cookies with the melted butter in a bowl and mix until the crumbs hold together when pressed. Press the mixture evenly over the bottom and about 1/2 inch up the sides of the prepared pan. Chill the crust in the fridge while you make the filling, at least 20–30 minutes.
• Whip the cream: in a chilled mixing bowl, whip the heavy cream with an electric mixer to soft peaks. Set aside in the fridge.
• Prepare the mascarpone base: in a separate bowl, beat the mascarpone with the brown sugar and vanilla until smooth and just combined — avoid overbeating so it doesn't become grainy.
• Fold the whipped cream into the mascarpone mixture gently with a spatula in three additions until the mixture is uniform and light — the texture should be silky and spreadable.
• Assemble the first layer: spread about half of the mascarpone cream over the chilled Speculoos crust and smooth the top with an offset spatula.
• Quickly dip each ladyfinger into the cooled coffee for 1 second per side (they should be moist but not soggy). Arrange a single even layer of dipped ladyfingers over the cream; break a few to fit if needed.
• Spread the remaining mascarpone cream over the ladyfingers and smooth the surface. Tap the pan gently on the counter to remove air pockets.
• Cover the springform pan tightly with plastic wrap and chill in the refrigerator at least 6 hours, preferably overnight, to let the layers meld and the filling firm up.
• To finish, release and remove the springform ring. Dust the top evenly with cocoa powder and scatter the reserved Speculoos crumbs around the edge. Slice and serve chilled.