Mix Oreo crumbs and melted butter in a bowl until fully combined. Press the mixture into the bottom of a 9-inch springform pan.
Bake the crust for 10 minutes and set it aside to cool. Meanwhile, make the filling.
Using a stand mixer or electric hand mixer, beat the cream cheese and sugar together until smooth.
Add in flour and vanilla. Mix until just combined.
Gradually add in eggs, mixing just until combined.
Mix in whiskey and melted chocolate until fully combined.
Pour the filling over the cooled crust.
Bake for 45-50 minutes or until the center is almost set. Cool completely on a wire rack.
Meanwhile, make the fudge brownie topping. In a saucepan, melt the butter. Add the sugar, cocoa powder, and salt. Stir to combine. Remove from heat and stir in the vanilla extract.
Add the eggs, one at a time, stirring vigorously after each addition. Stir in flour until fully combined.
Spread the brownie topping over the cooled cheesecake. Cover and refrigerate for at least 2 hours or until set.
Remove sides of the springform pan and slice the cheesecake to serve. Enjoy!