Preheat the oven to 325°F (163°C).

Make the crust by combining graham cracker crumbs and melted butter in a bowl, mixing until it resembles wet sand. Press mixture firmly into the bottom of a lined square baking pan. Bake for 8–10 minutes until lightly golden, then let it cool.

Prepare the cheesecake filling by beating cream cheese and sugar until smooth. Add eggs one at a time, beating well after each addition. Mix in sour cream and vanilla extract.

Melt chocolate chips until smooth, then fold into one-third of the cheesecake mixture.

Pour half of the plain cheesecake mixture onto the cooled crust. Add dollops of the chocolate mixture followed by the rest of the plain mixture. Use a knife to swirl chocolate into the cheesecake.

Bake for 30–35 minutes until the center is slightly jiggly.

Turn off the oven and let the cheesecake cool inside for an hour.

Transfer to the fridge and chill for at least 2 hours or overnight to set fully.

Cut into squares, serve, and enjoy!