Preheat oven to 350°F. Generously spray a 12-cup muffin tin with nonstick cooking spray, making sure to coat the bottom, sides, and top of the pan. Optional: Cut small strips of parchment paper and lay one across the bottom of each cup with ends sticking up for easy removal.
Unroll the first pie crust onto a lightly floured surface. Roll gently to a 12-inch circle, about ⅛-inch thick. Using a 3-inch round cookie cutter or drinking glass, cut out 12 circles, positioning them close together to minimize waste.
Gently press each circle into a muffin cup, molding it against the bottom and sides. The dough should come about halfway up each cup. Check for tears or holes. Repeat with the second crust. Gather scraps, reroll, and cut more circles for a total of 24 crusts.
In a large mixing bowl, whisk together brown sugar, melted butter, and corn syrup until smooth and the sugar begins to dissolve with no butter streaks remaining.
Add vanilla extract, cinnamon, and salt to the mixture. Whisk until glossy and well combined.
Fold in the chopped pecans and stir until every piece is coated with the sweet mixture.
Add the lightly beaten eggs and stir gently but thoroughly until everything is combined into a uniform mixture. Do not overmix.
Carefully fill each crust about two-thirds full (approximately 1½ tablespoons per cup). The filling will look liquidy but will set during baking.
Bake for 18-20 minutes until crust edges are golden brown, filling is set around the edges, and the center is still slightly jiggly. Do not overbake.
Remove from oven and let sit in the pan for at least 10 minutes. The filling will continue to set during this time. After 10 minutes, carefully transfer to a wire rack to cool completely.