Mix the cream cheese and sugar:

In a large mixing bowl, add softened cream cheese and beat until smooth and lump-free. Add sugar and mix until completely dissolved. Avoid overmixing to prevent cracking during baking.

Add eggs gradually:

Beat in 1 egg and mix for 30 seconds until smooth. Then add the remaining egg and egg yolk, one at a time, ensuring each addition is fully incorporated before adding the next.

Combine cream, starch, and Oreos:

Pour in the heavy cream and stir gently until blended. Fold in cornstarch and fold until no dry bits remain. Finally, fold in the crushed Oreos gently just until evenly distributed — don't overmix, or they'll soften too much.

Prepare the pan:

Line a 6-inch springform pan with parchment paper. Pour in the batter and gently tap the pan a few times to release air bubbles.

Bake:

Preheat your oven to 230°C (446°F) and bake the cheesecake in the center rack for about 30 minutes. Don't open the oven while baking — temperature drops can cause the cake to sink.

Cool completely:

The cheesecake is done when the surface is evenly browned and slightly burnt, with a jiggly center. Let it cool completely to room temperature — it will continue to set as it cools.

Melt the chocolate and butter:

In a heatproof bowl, combine chopped dark chocolate and butter. Place over a pot of warm water (50–60°C) and stir until melted and silky smooth.

Add cream:

Pour in the heavy cream and stir until the mixture becomes glossy and smooth. Let it cool to room temperature — it should remain pourable but not hot.

Pour the ganache:

Once the cheesecake has cooled, pour the room-temperature ganache evenly on top. Smooth it with a spatula.

Chill:

Refrigerate for at least 4 hours or overnight until the ganache is completely set.

Decorate:

Before serving, dust the top with cocoa powder using a fine sieve for that perfect bakery-style finish.