Preheat the oven to 350 degrees Fahrenheit.
Add the brown sugar, pecans, egg, butter, and vanilla to a medium bowl and stir together until just combined. 14 TBS Brown Sugar, 3/4 cup Chopped Pecans, 1 Egg, 1 TBS Unsalted Butter, 1 tsp Vanilla Extract
Add a small spoonful of the filling into each tart shell to fill them about 3/4 of the way full.
Bake for 20 to 25 minutes, or until the crust is golden brown and the tops are set.
Let the tarts cool in the pan for about 10 minutes, then use a knife to loosen the edges of the tarts and transfer them each to a cooling rack.
Let cool completely, then dust with powdered sugar if desired.