Preheat the oven to 325°F. Line muffin tins with cupcake liners.

Melt the chocolate chips in a small bowl by microwaving in 30 second increments and stirring between each session until smooth and fully melted. Set aside to cool. (You can also use a chocolate melting pot or a double boiler to melt chocolate.)

Pulverize Oreo cookies in food processor until fine crumbs form.

Add melted butter and pulse a few more times until mixture is fully combined.

Scoop about 1 tablespoon of cookie crumbs into each cavity of prepared muffin tins. Pack down the crumbs with a small mallet or the bottom of a cup.

In a large mixing bowl, beat the cream cheese until smooth and fluffy.

Add sugar, cocoa powder, and vanilla extract and beat until fully combined.

Beat in cooled chocolate, flour, and sour cream. Add in espresso and Kahlua and stir or beat carefully (to prevent splatter) until combined.

Add in 1 egg at a time and stir by hand until combined.

Scoop cheesecake mixture over the packed oreo crumbs in the muffin tin. Fill each tin almost to the top.

Bake 20 minutes until the cheesecakes are set and dry to the touch on top.

Allow cheesecakes to cool to room temperature (about 30 minutes) and then place in the refrigerator to chill for 1-2 hours.

Whip heavy cream until stiff peaks form and pipe swirls on top of the cheesecakes. Sprinkle with cocoa powder and serve.