Wrap the outside of a 9-inch springform pan with two layers of aluminum foil.
Put the cookies in a food processor and pulse until crumbs form.
Add the butter and process until the mixture looks like wet sand.
Press into the bottom and up the sides of the pan.
Add the cream cheese, ricotta, eggs, sugar, and vanilla to the food processor. Process until smooth.
Pour into the crust. Sprinkle the chocolate chips on top. Swirl in gently, leaving most on the top.
Put the pan into a large roasting pan and add 2 inches of boiling water. This helps prevent cracks.
Bake for 45-55 minutes or until the center only jiggles slightly.
Let cool to room temperature. Cover with plastic wrap and refrigerate for at least 4 hours before serving.
Notes
One of the best ways to prevent cracks is to not open the oven door. Bake the cheesecake for 50 minutes and turn the oven off. Wait an hour to open the door and remove the cheesecake.