In a bowl, combine Oreo cookie crumbs and melted butter until evenly moistened. Press firmly into the bottom of a 9-inch springform pan. Chill in the freezer while you prepare the filling.

In a heatproof bowl, melt semi-sweet chocolate chips with heavy cream until smooth. Stir in Godiva chocolate liqueur and let the mixture cool slightly.

In a large mixing bowl, beat the softened cream cheese and sugar until creamy. Add the eggs one at a time, mixing well after each addition. Blend in sour cream, vanilla extract, cocoa powder, and flour. Finally, mix in the melted chocolate mixture until fully incorporated.

Pour the filling into the prepared crust. Tap the pan to release air bubbles. Place the pan on a rack in the center of a preheated oven and bake at 325°F for 60–70 minutes, or until the center is just set. Turn off the oven, crack the door, and let it cool inside for 1 hour.

Remove the cheesecake from the oven and refrigerate for at least 4 hours or overnight. Before serving, top with a rich chocolate ganache and optional whipped cream or chocolate shavings.