01 - Preheat oven to 350°F. Grease a 12-cup mini muffin pan thoroughly with cooking spray or butter.
02 - Combine flour and salt in a mixing bowl. Cut in cold cubed butter using a pastry blender or two forks until mixture resembles coarse crumbs. Sprinkle cold water over the mixture, 1 tablespoon at a time, tossing gently with a fork until dough just holds together when pressed.
03 - Roll dough out on a lightly floured surface to 1/8-inch thickness. Cut twelve 3-inch circles using a round cookie cutter or glass. Gently press each circle into the wells of the mini muffin tin, pressing up the sides to form cups.
04 - Whisk together brown sugar, corn syrup, melted butter, egg, vanilla, and salt in a medium bowl until completely smooth. Fold in chopped pecans until evenly distributed.
05 - Spoon filling evenly into prepared crusts, approximately 1 tablespoon per mini pie. Bake for 22-25 minutes until filling is set and crust is golden brown. The centers should still be slightly jiggly but not liquid.
06 - Let pies cool in the pan for 10 minutes before carefully removing. Transfer to a wire rack to cool completely. Serve plain or topped with whipped cream if desired.