Preheat oven to 325°F (160°C).
Prepare the crust: mix crushed cookies, melted butter, and sugar. Press into the bottom of a 9-inch springform pan.
Mix cheesecake batter: beat cream cheese and sugar until smooth. Add eggs one at a time, then vanilla, sour cream, and heavy cream.
Fold in melted chocolate until just combined.
Bake in a water bath for 60–65 minutes, until edges are set but center jiggles slightly.
Cool gradually: turn off oven, crack door, and let cheesecake cool inside for 1 hour. Then refrigerate at least 4 hours or overnight.
Cook cherry topping: simmer cherries, sugar, and cornstarch until thickened. Stir in kirsch (if using). Cool completely.
Spread cherry topping over chilled cheesecake. Whip cream with powdered sugar, pipe or spread on top, and garnish with dark chocolate shavings.