Preheat oven to 350°F if toasting the crust lightly. Crush Oreo cookies in a food processor until fine crumbs.

Combine crumbs with melted butter in a bowl until the mixture resembles wet sand. Press into the bottom of a springform pan to form a solid crust. Set aside.

Beat softened cream cheese and powdered sugar with an electric mixer on medium speed until smooth and creamy, about 2-3 minutes.

Add melted semi-sweet chocolate, cocoa powder, and vanilla extract. Mix well until a rich chocolate filling forms.

In a separate bowl, whip heavy cream on high speed until stiff peaks form, about 3-4 minutes; fold into chocolate mixture gently.

Spread the chocolate filling evenly over the crust and smooth the top. Cover with plastic wrap and refrigerate for at least 4 hours until set.

Carefully remove from springform pan, slice into wedges, and serve with optional toppings like fresh berries or whipped cream.