Preheat oven to 350 degrees F. and position rack in center of oven (too high or too low of rack placement will cause baking problems). Lightly grease (butter) a 9-inch springform pan.
Prepare Chocolate Crust; set aside to cool before using.
In a large bowl, combine cream cheese and sugar; cream just until light and fluffy. Add eggs, one at a time, beating after each addition. NOTE: Do not over beat the mixture. You want to avoid beating air into the mixture. Too much air will make the cheesecake fall. Beat in flour, salt, whipping cream, and vanilla extract; set aside.
In a medium bowl, place 1 1/2 cups of the cream cheese mixture. Gradually add melted chocolate; stir until well combined. Stir in chocolate chips; set aside.
Pour all but 2 cups of remaining cream cheese mixture over prepared cookie crust. Spoon chocolate filling in a 2-inch wide ring onto the cream cheese mixture (approximately 1 1/2 inches from the edge of pan). Using the back of a spoon, carefully press chocolate mixture down until top is level. Spoon reserved cream cheese mixture evenly over all; smooth top with the back of a spoon (this helps get rid of any extra air bubbles).
Place cheesecake in center of middle oven rack. Position a baking pan filled halfway with hot water on lower rack. Bake 15 minutes. Reduce heat to 300 degrees F. Bake another 1 hour or until edges are light brown and center is almost set. NOTE: There should be no wet spots or liquid areas in the center of the cheesecake. Remember that a cheesecake continues to cook when it is removed from the oven.
How to prevent cracks in your cheesecake: When the internal temperature of a cheesecake rises beyond 160 degrees F. while baking, it will always crack. To prevent this from happening, use an instant-read cooking thermometer to test its doneness. Take it out of the oven when the cheesecake reaches 150 degrees F. at the center to avoid over baking.
Turn oven off. Let cake stand in oven, with door ajar, 30 minutes or until center is completely set. remove from oven and cool completely on a wire rack. A wonderful looking baked cheesecake (with no cracks), can crack as it sits on the cooling rack because the cake shrank during cooling and clung to the sides of the springform pan. To avoid this from happening, cool the cheesecake for only a few minutes, and then, using a paring knife, free it from the sides of the pan before allowing it to cool completely.
Prepare Chocolate Sour Cream Topping. Spread topping over top of cooled cheesecake. Sprinkle grated chocolate in a 2-inch band around the outer edge of top. Cover with plastic wrap and refrigerate 12 to 24 hours before cutting (the cheesecake will solidify to a perfect consistency during this time).
To serve, slide a small knife around edge of cake to loosen it and remove sides of the springform pan; transfer onto a cake plate.
Makes 10 to 12 servings.
In a food processor, whirl cookie crumbs to fine crumbs. Add butter; whirl 5 to 10 seconds more. Put crumb mixture onto bottom of prepared pan, being careful not to get crumbs on sides of pan. Press crumb mixture firmly and evenly over the bottom.
Bake 10 minutes. Remove from oven and cool crust completely on a wire rack. Maintain oven temperature to bake the cheesecake.
In a medium bowl, combine sugar, cocoa, sour cream, and vanilla extract.
* To quickly bring cream cheese to room temperature, place unwrapped package(s) in a microwaveable bowl. Microwave on HIGH for 30 to 45 seconds or until slightly softened. Do not let it melt or get warm. Refrigerate if it does.
** Learn different techniques for How To Melt Chocolate.
NOTE: Use a conventional (regular) oven rather than a convection oven in baking your cheesecake. The forced hot air from the convection oven causes too much browning and can often cause the center of the cheesecake to collapse.
Chocolate Fudge Cheesecake Recipe: https://whatscookingamerica.net/cake/chocfcheesecake.htm