Crush 30 Oreo cookies (with filling) into fine crumbs using a food processor or a zip-top bag and rolling pin. Mix the crumbs with melted butter until evenly coated. Press the mixture firmly into the bottom of a 9-inch springform pan to form an even crust.

Place the crust in the refrigerator for 15–20 minutes to set. This helps it hold together when you add the filling. You can also pop it in the freezer for 10 minutes to speed things up.

In a large bowl, use an electric mixer to beat the softened cream cheese until smooth and creamy. Add powdered sugar, vanilla extract, and sour cream (if using), mixing until fully combined. Scrape down the sides of the bowl as needed.

In a separate bowl, whip 1 1/4 cups cold heavy cream until stiff peaks form. This takes about 2–3 minutes with an electric mixer. Be careful not to overwhip, as it can turn grainy.

Gently fold the whipped cream into the cream cheese mixture using a spatula. Add the coarsely chopped Oreo cookies and fold until evenly distributed. The filling should be light and fluffy.

Spread the filling evenly over the chilled Oreo crust, smoothing the top with a spatula. Cover the pan with plastic wrap or foil. Refrigerate for at least 6 hours, preferably overnight, to set.

Whip 1 cup cold heavy cream with 1/4 cup powdered sugar until stiff peaks form. Spread or pipe the whipped cream over the chilled cheesecake. Sprinkle with chopped Oreo cookies and drizzle with chocolate syrup, if desired.

Remove the cheesecake from the springform pan by running a knife around the edges and releasing the sides. Slice into wedges and serve chilled. Store leftovers in the refrigerator.