01 - Preheat oven to 325°F. Line a standard 12-cup muffin tin with paper cupcake liners.
02 - Combine graham cracker crumbs, melted butter, and sugar in a mixing bowl. Stir until the mixture resembles wet sand and holds together when pressed.
03 - Divide the crumb mixture evenly among the 12 lined muffin cups. Press firmly into the bottom of each cup using the back of a spoon or a small measuring cup to create a compact, even crust layer.
04 - In a separate bowl, beat the softened cream cheese and sugar together using an electric mixer or whisk until completely smooth and free of lumps.
05 - Add the egg and vanilla extract to the cream cheese mixture. Mix until just combined — do not overmix. Gently fold in the sour cream until evenly incorporated.
06 - Spoon or pipe the cheesecake filling evenly over each prepared crust, filling each cup nearly to the top. Smooth the surface with a spatula.
07 - Bake for 18 to 20 minutes, or until the centers are set but still have a slight jiggle when gently shaken. Avoid overbaking to prevent cracking.
08 - Remove from the oven and allow the mini cheesecakes to cool in the muffin tin for 15 minutes at room temperature.
09 - Transfer the cheesecakes to a wire rack to cool completely, then refrigerate for at least 1 hour to set the filling firmly.
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.