Step 1: Prepare the Crust

1. Preheat the Oven: Preheat your oven to 325°F (165°C). Line a standard muffin tin with 12 cupcake liners.
2. Mix the Ingredients: In a medium mixing bowl, combine the graham cracker crumbs, granulated sugar, and melted butter. Stir until the mixture resembles wet sand.
3. Form the Crusts: Spoon about 1 tablespoon of the crust mixture into each cupcake liner. Press down firmly with the back of a spoon or a small glass to form a compact layer.
4. Bake: Bake the crusts for 5 minutes to set, then remove from the oven and let them cool while you prepare the filling.

Step 2: Make the Cheesecake Filling

1. Beat the Cream Cheese: In a large mixing bowl, beat the softened cream cheese with an electric mixer until smooth and creamy, about 2 minutes.
2. Add Sugar and Egg: Add the granulated sugar and beat until well combined. Then, add the egg and vanilla extract, mixing until just combined. Avoid over-beating the mixture, as this can cause cracks in the cheesecakes.
3. Fold in Sour Cream: Gently fold in the sour cream to add creaminess and prevent the filling from being too dense.
4. Fill the Cups: Spoon the cheesecake filling over the cooled crusts, filling each cup about 2/3 full. Smooth the tops with a spoon.

Step 3: Bake the Cheesecakes

1. Bake: Place the muffin tin in the preheated oven and bake for 18-20 minutes, or until the cheesecakes are set but still slightly jiggly in the center.
2. Cool: Remove from the oven and let the cheesecakes cool in the pan for 10 minutes. Then transfer the cheesecakes to a wire rack to cool to room temperature.
3. Chill: Place the cheesecakes in the refrigerator to chill for at least 2 hours, or until completely set.

Step 4: Make the Pecan Pie Topping

1. Combine Ingredients: In a small saucepan, combine the brown sugar, corn syrup, melted butter, and vanilla extract. Cook over medium heat, stirring constantly until the sugar is dissolved and the mixture is smooth.
2. Add Pecans: Remove the saucepan from heat and stir in the chopped pecans.
3. Cool Slightly: Let the pecan topping cool for a few minutes to thicken slightly before spooning it onto the cheesecakes.

Step 5: Assemble and Serve

1. Top the Cheesecakes: Spoon a generous tablespoon of the pecan pie topping over each cheesecake, spreading it gently to cover the top.
2. Chill Again: For best results, return the cheesecakes to the refrigerator to chill for an additional hour, allowing the topping to set.
3. Serve: Remove the cupcake liners before serving, if desired, and enjoy!