Melt butter and combine with sugar and cocoa powder.

Stir in graham cracker crumbs until well combined.

Press the crumb mixture evenly over the bottom of a greased 9-inch springform pan.

Bake the crust at 350F for 10 minutes.

Let the crust cool completely and grease the sides of the pan.

Beat cream cheese until smooth and creamy.

Gradually beat in sugar until well combined.

Beat in eggs, one at a time, until just combined.

Blend in Bailey's Irish Cream until smooth.

Pour about 1/3 of the cream cheese mixture into a separate bowl.

Stir in melted semisweet chocolate into the smaller bowl of cream cheese mixture.

Pour half of the plain cream cheese mixture into the prepared springform pan.

Drizzle with half of the chocolate cream cheese mixture.

Repeat the layers with the remaining plain and chocolate mixtures.

Create a marbled design by gently swirling the batter with a knife.

Bake the cheesecake for 10 minutes at 450F.

Reduce the oven temperature to 250F and bake for 55 minutes.

Let the cheesecake cool completely in the oven with the door slightly ajar.

Refrigerate the cheesecake for several hours or preferably overnight before serving.