Step 1: Preheat oven to 350°F (175°C). Wrap the outside of a 9-inch springform pan with heavy-duty aluminum foil to prevent water from seeping in if using a water bath. Lightly grease the bottom of the pan.
Step 2: In a medium bowl, combine the chocolate cookie crumbs, ¼ cup granulated sugar, and melted butter. Press the mixture evenly into the bottom of the prepared springform pan. Bake for 8-10 minutes, then remove from oven and let cool slightly.
Step 3: Reduce oven temperature to 325°F (160°C).
Step 4: In a large bowl, using an electric mixer on medium speed, beat the softened cream cheese until smooth and creamy, about 2-3 minutes.
Step 5: Gradually add ½ cup granulated sugar to the cream cheese, beating until just combined and smooth, scraping down the sides of the bowl as needed.
Step 6: Beat in the eggs one at a time, mixing on low speed until just incorporated after each addition. Be careful not to overmix.
Step 7: Stir in the sour cream and vanilla extract until smooth. Gently fold in the melted and slightly cooled dark chocolate.
Step 8: Pour the cheesecake batter over the cooled crust in the springform pan. Place the springform pan into a larger roasting pan. Fill the roasting pan with hot water, reaching about halfway up the sides of the springform pan.
Step 9: Bake for 60-70 minutes, or until the edges are set but the center still jiggles slightly when gently shaken. Turn off the oven, crack the door open, and let the cheesecake cool in the oven for 1 hour.
Step 10: Remove the cheesecake from the water bath and the oven. Let it cool completely on a wire rack at room temperature. Once cool, cover and refrigerate for at least 6-8 hours, or preferably overnight, to allow it to set completely.
Step 11: Before serving, prepare the whipped cream topping: In a large, chilled bowl, whip the heavy cream, powdered sugar, and vanilla extract on high speed until stiff peaks form.
Step 12: Carefully remove the cheesecake from the springform pan. Spread the cherry pie filling evenly over the top of the chilled cheesecake.
Step 13: Pipe or spread the whipped cream topping around the edge of the cheesecake or over the entire top. Garnish with chocolate shavings or curls. Slice and serve cold.