Prepare the Crust. Preheat the oven to 350°F. Mix the graham cracker crumbs, brown sugar, and melted butter until the crumbs are evenly moistened. Line a muffin tin with cupcake liners and press about 1 1/2 tablespoons of the mixture into the bottom of each liner. Bake for 5 minutes, then let the crusts cool.
Make the Cheesecake Filling. Beat the softened cream cheese and sugar until smooth. Add the eggs one at a time, mixing after each addition. Blend in the vanilla extract and sour cream until the filling is creamy and well combined.
Fill the Muffin Cups. Divide the cheesecake mixture evenly among the prepared liners, leaving about 1/4 inch of space at the top.
Bake the Cheesecakes. Bake for 18–20 minutes, until the centers are set around the edges but still jiggle slightly. Remove from the oven and let the cheesecakes cool completely at room temperature.
Chill Until Firm. Refrigerate the cooled cheesecakes for at least 2 hours or overnight. Chilling helps them firm up so they're easier to handle and ready for the pecan topping.
Make the Pecan Topping. In a small saucepan, melt the butter and brown sugar over medium heat. Bring to a simmer and cook for 3 minutes. Stir in the corn syrup and simmer for 1 minute longer. Remove the pan from the heat and stir in the vanilla and heavy cream, whisking until smooth. Fold in the chopped pecans and let the mixture sit for 5–10 minutes.
Add the Topping. Spoon the pecan mixture generously over each chilled cheesecake. Return the cheesecakes to the refrigerator for at least 2 hours so the topping and filling can set.
Serve. Arrange the finished cheesecakes on a serving platter. Leave them in the liner for easy grab-and-go desserts, or remove the liners for a prettier presentation. Makes about 18 mini cheesecakes.
Notes
Recipe Tips
Start with room-temperature cream cheese. This helps the filling blend smoothly and prevents lumps.
Don't overbake. The centers should still jiggle slightly when you take the cheesecakes out of the oven.
Allow plenty of chilling time. These cheesecakes are delicate when warm. Chill them thoroughly before removing the liners or adding the topping.
Let the pecan topping cool slightly. Let it sit for 5–10 minutes before spooning it over the cheesecakes so it thickens a little.
Make them ahead. Bake the cheesecakes the day before your gathering and add the topping. Let everything chill and set before serving.