Preheat oven to 350°F (177°C). Line muffin pan with cupcake liners.
In a small bowl, combine the graham cracker crumbs, granulated sugar, melted butter, and salt. Mix well.
Place about 2 tablespoons of graham cracker crumbs in each muffin cup. Press firmly with the back of a spoon to pack the crumb mixture.
Bake for 5 minutes. Remove from the oven and allow to cool slightly while making the filling.
In a large mixing bowl, beat the cream cheese with an electric mixer for 1 minute. Add the granulated sugar and beat an additional 2 minutes, until the mixture is fluffy and there are no cream cheese chunks.
Scrape the sides of the bowl and add in the flour. Mix on low speed until just incorporated. You do not want to add too much air into the mixture, so from this point forward, mix on low speed only.
Add the vanilla extract and lemon juice to the bowl and mix on low speed.
Scrape the sides of the bowl and add the eggs, one at a time, mixing on low speed after each addition, until the egg is almost fully mixed in.
Add the sour cream and mix on low speed until it is incorporated.
Fill each muffin cup with about ¼ cup of batter, filling to the rim of the liners. Bake cheesecakes at 350°F (177°C) for 18-20 minutes, or until the outside of each cheesecake is set, but the middle is still jiggly.
Turn the oven off and open the oven door. Allow to cool in the oven for 30-60 minutes, then remove and refrigerate for at least 2 hours.
Water bath: To help keep the cheesecake from cracking, fill a roasting pan with boiling water and place it on the rack underneath the cheesecake. The batter makes enough for 15 mini cheesecakes. You can line 3 cups of an additional muffin tin and cook alongside the first, or cook the remaining batter after the first batch has cooled.Bite-sized cheesecake: Line a mini-muffin pan with mini muffin cups. Press 2 teaspoons of graham cracker mixture into each muffin cup. Bake at 350°F for 4 minutes. Fill the mini muffin cups with the cheesecake filling and bake for 10-12 minutes.