Place the 300 g speculoos biscuits in a resealable bag and crush them into fine crumbs with a rolling pin.

Melt the 100 g butter in the microwave, then combine it with the crushed speculoos biscuits in a mixing bowl.

Press the buttery biscuit mixture firmly into the bottom of a springform pan. Refrigerate the crust for 15 minutes.

Beat the 300 ml heavy cream in a chilled mixing bowl with an electric mixer until stiff peaks form.

Mix the 350 g cream cheese, 250 g mascarpone, 60 g speculoos spread, and 30 g icing sugar in another mixing bowl until smooth.

Fold the whipped heavy cream into the cream cheese mixture gently until the filling is uniform and airy.

Spread the filling evenly over the chilled biscuit crust. Smooth the surface with an offset spatula.

Refrigerate the cheesecake for at least 4 hours, preferably overnight, before unmolding and serving cold.