Preheat oven to 350°F (175°C). Grease a 9-inch springform pan.
Combine crushed Reese's cups and melted butter. Press into the bottom of the prepared pan.
In a large bowl, beat cream cheese and sugar until smooth. Beat in vanilla. Add eggs one at a time, beating until just combined.
Pour filling over crust. Bake for 60-70 minutes, or until set around the edges but still slightly wobbly in the center. Let cool completely in the oven with the door ajar.
For the ganache, heat heavy cream in a saucepan over medium heat. Remove from heat and add chocolate chips. Let stand for 1 minute, then stir until smooth. Pour over cheesecake.