01 - Preheat oven to 325°F. Line a standard 12-cup muffin tin with paper liners and set aside.
02 - In a medium bowl, combine graham cracker crumbs, melted butter, and sugar. Stir until the mixture resembles wet sand and holds together when pressed.
03 - Divide the crumb mixture evenly among the 12 muffin cups. Using the back of a spoon or a small measuring cup, press firmly to create a compact, even crust layer.
04 - In a large bowl, beat softened cream cheese and sugar together using an electric mixer on medium speed until completely smooth and creamy, scraping the bowl as needed.
05 - Add the egg and vanilla extract to the cream cheese mixture. Beat on low speed until just combined. Gently fold in the sour cream with a spatula, being careful not to overmix.
06 - Spoon or pipe the cheesecake filling evenly over each prepared crust, filling each liner nearly to the top. Smooth the surfaces with a small spatula.
07 - Bake for 18 to 20 minutes, or until the centers appear set but still have a slight jiggle when gently shaken. Avoid overbaking to prevent cracking.
08 - Remove from the oven and allow the cheesecakes to cool in the muffin tin for 15 minutes at room temperature. Then transfer them to a wire rack to cool completely.
09 - Refrigerate the mini cheesecakes for at least 1 hour, or until thoroughly chilled, to allow the filling to set properly.
10 - Top each mini cheesecake with your choice of fresh berries, lemon curd, melted chocolate, caramel sauce, chopped nuts, crushed cookies, or fruit preserves. Serve chilled.