Preheat oven to 325°F and line a 12-cup muffin tin with paper liners.
Mix crumbs and butter; press 1 tbsp into each liner for the crust.
Beat cream cheese and sugar until smooth, add egg and vanilla, mix just until combined.
Spoon filling over crusts about 3/4 full. Bake 12–15 minutes until set at the edges. Cool in pan.
Heat cream until simmering, pour over chopped chocolate, stir until glossy ganache forms; cool slightly.
Spoon ganache over cooled cheesecakes and chill at least 1 hour. Sprinkle sea salt or add berries before serving.