Chocolate Crust

Preheat the oven to 350°F (conventional). Butter the bottom of a 10-inch springform pan.

Pulse the chocolate cookies with melted butter until fine crumbs form.

Press the mixture firmly into the bottom of the pan, slightly up the sides.

Bake for 7–8 minutes and set aside to cool.

Cheesecake Filling

Reduce oven temperature to 320°F.

Beat cream cheese, mascarpone, sugar, vanilla, and salt on medium-low speed until smooth.

Lightly whisk eggs separately, then add slowly, mixing just until combined.

Add heavy cream, sour cream, and sifted cornstarch. Mix gently until smooth.

Assembly and Baking

Dip ladyfinger biscuits quickly into the coffee and arrange over the cooled crust.

Pour cheesecake batter over the ladyfingers and smooth the top.

Bake for 75–85 minutes until the edges are set and the center slightly jiggles.

Turn off oven, crack the door, and let the cheesecake cool inside for 1 hour.

Chill in the refrigerator for at least 6 hours or overnight.

Coffee Mascarpone Cream

Whip mascarpone, sugar, and coffee mixture until smooth.

In a separate bowl, whip cream to soft peaks.

Fold whipped cream into mascarpone mixture gently.

Spread over chilled cheesecake and dust with cocoa powder.