Preheat the oven to 325°F. Line the muffin pan with 12 muffin liners (or, you can also grease the muffin holes, but the cheesecakes will be much more difficult to remove and may fall apart).
In a medium bowl, combine the graham cracker crumbs, sugar, and butter with a fork.
Divide the crust evenly among the muffin liners. Press a rounded tablespoon of the crust mixture into each muffin liner, and add more if you have extra crust mixture leftover. Make sure to press the crust firmly into the liner. Put the muffin pan in the oven, and bake the crusts for five minutes. Then remove from the oven and allow the crusts to cool.
With a mixer, beat the cream cheese and sugar together until creamy. Then add the sour cream, lemon juice, and vanilla together. Then add the eggs and beat gently until combined with the other ingredients.
Divide the cream cheese mixture evenly between all the muffin cups. Put the cheesecake mixture on top of the crusts, filling each muffin cup about 3/4 full.
Bake at 325°F for about 25-35 minutes or until the cheesecakes are set and no longer jiggly.
Set the muffin pan on a wire rack and cool cheesecakes completely before removing.
Refrigerate for 1-2 hours or until ready to serve. Add toppings of your choice and serve.