1. Preheat your oven to 350 F (175 C). Line a 12-cup muffin tin with paper liners.

2. In a medium bowl, combine the graham cracker crumbs, 1/3 cup granulated sugar, and melted butter. Stir until the crumbs are evenly moistened.

3. Divide the graham cracker mixture evenly among the 12 muffin cups. Use the back of a spoon or your fingertips to firmly press the crust mixture into the bottom of each liner.

4. In a large bowl, using an electric mixer, beat the softened cream cheese and 1 cup granulated sugar together until smooth and creamy.

5. Beat in the eggs one at a time, mixing just until combined after each addition. Stir in the vanilla extract and sour cream until the mixture is uniform and silky.

6. Spoon the cheesecake filling evenly over the prepared crusts in each muffin cup. Fill each cup about 3/4 full.

7. Bake for 20-25 minutes, or until the edges are set and the centers are still slightly jiggly when you gently shake the pan.

8. Remove the muffin tin from the oven and let the cheesecakes cool completely on a wire rack. Once cooled to room temperature, transfer the muffin tin to the refrigerator and chill for at least 2 hours, or preferably overnight, before serving.