Preheat oven to 325°F (160°C). Grease and line the bottom of a 9" springform pan.
Mix cookie crumbs and melted butter. Press firmly into the pan bottom. Bake for 10 minutes. Cool slightly.
In a large bowl, beat softened cream cheese until smooth. Add sugar, sour cream, and vanilla; mix well.
Stir in melted chocolate. Add eggs one at a time, mixing on low until just combined.
Pour batter over crust. Tap gently to remove air bubbles.
Bake for 55–65 minutes, until center is slightly jiggly. Cool 1 hour, then chill at least 4 hours or overnight.
For ganache: heat cream until steaming, pour over chopped chocolate. Let sit 2 mins, then stir smooth.
Pour ganache over chilled cheesecake. Spread evenly and chill until set.