Preheat the oven to 325°F (160°C).

1. In a medium bowl, mix the graham cracker crumbs, sugar, and melted butter until the mixture resembles wet sand. Spoon about 1 tablespoon of the crust mixture into each cup of a muffin tin (preferably lined with paper liners). Press the crumbs down firmly with the back of a spoon.
2. In a large bowl, beat the cream cheese and sugar together until smooth and creamy. Add the vanilla extract and eggs, one at a time, mixing well after each addition.
3. Add the sour cream and mix until combined. Stir in the flour until smooth, then fold in the mini chocolate chips.
4. Spoon the cheesecake batter into each muffin cup over the crust. Fill about 2/3 of the way up.
5. Bake for 18–20 minutes, or until the cheesecakes are set around the edges but slightly jiggly in the center.
6. Allow the cheesecakes to cool at room temperature for about 30 minutes, then transfer to the fridge to chill for at least 2 hours or overnight.
7. Once chilled, remove the cheesecakes from the muffin tin and serve. Optionally, top with extra mini chocolate chips before serving.