Massive Chocolaty Cheesecake

Crust:
Make sure the oven rack is in the center position and preheat the oven to 375 degrees F. In a large mixing bowl, combine all the crust ingredients with a fork and mix until well combined. Press the cookie mixture into the bottom of a 9-inch springform pan. Bake the crust until fragrant and just set, about 8 to 10 minutes. Using oven mitts or pot holders, remove from the oven and cool for at least 15 minutes before adding the filling. Lower the oven temperature to 350 degrees F.

Filling:
Place semi-sweet chocolate in a microwave-proof glass bowl or measuring cup and cover it with plastic wrap. Microwave the chocolate on high power for 30 seconds; then stir it with a spoon or rubber spatula. Continue to microwave the chocolate on high, stopping to stir every 30 seconds, until it is completely melted and smooth. (If you don't have a microwave, you can use the double-boiler method for melting chocolate.) Set aside. Place the cream cheese, sugar, and vanilla extract in a large metal bowl and, using an electric mixer, beat until creamy and smooth, about 4 minutes. Turn the mixer off and scrape down the sides of the bowl with a rubber spatula. Sift the cocoa powder into the cream cheese mixture and beat to incorporate. Turn the mixer off. Crack and add the eggs 1 at a time, beating well after each addition. Be sure to turn the mixer off before you add each egg. *Add the sour cream and melted chocolate and beat until smooth. Using a rubber spatula, transfer the batter to the prepared pan with the baked crust.

Bake at 350 degrees F until the cake rises and puffs and the center is just set and still slightly wiggly, about 1 hour and 10 minutes. Using oven mitts or pot holders, remove from the oven and place on a wire rack to cool.