Line the base of a 9-inch/23-cm springform pan with parchment paper. Crush the chocolate sandwich cookies into fine, even crumbs, then stir them with the melted butter until every crumb looks lightly moistened.

Press the cookie mixture firmly into the base of the prepared pan, using the bottom of a glass or measuring cup to create a compact, level layer. Refrigerate the crust for 20–30 minutes while preparing the filling.

Melt the chopped chocolate gently in a heatproof bowl set over barely simmering water, or microwave it in short bursts, stirring between each burst. Stir until smooth and let it cool until lukewarm.

Beat the softened full-fat cream cheese with the sifted confectioners’ sugar and vanilla until smooth and creamy. Stop mixing once the ingredients are combined, because excessive beating can add too much air and make the chilled cheesecake less firm.

In a separate cold bowl, beat the 240 ml of heavy cream to soft or medium peaks. The cream should hold gentle ridges from the beaters without becoming grainy or stiff.

Mix the lukewarm melted chocolate into the cream-cheese mixture until evenly colored and smooth. Fold in the whipped cream in two or three additions, using a broad spatula and stopping as soon as no white streaks remain.

Spoon the chocolate filling over the chilled crust and smooth the top with an offset spatula or the back of a spoon. Tap the pan very lightly on the counter to remove large air pockets, then cover it.

Refrigerate the cheesecake for at least 6 hours, preferably overnight, until the filling is firm throughout. Do not rush this stage, since the chocolate and whipped cream need time to set the filling.

For the strawberry glaze, warm the jam with the water and optional lemon juice until loosened and glossy. Set it aside to cool slightly while you hull and slice the strawberries.

Arrange the sliced strawberries over the cold cheesecake just before serving, then brush them lightly with the warm jam glaze. Remove the cheesecake from the springform pan while it is still cold and decorate with whipped cream, chocolate curls, or extra strawberries if desired.

For clean slices, dip a sharp knife in hot water, wipe it completely dry, and cut through the cake. Repeat the warming and drying process between cuts for smooth, bakery-style portions.