**Preheat Oven:**
Preheat your oven to 350°F (175°C). Place the phyllo shells on a baking sheet.
**Prepare Filling:**
In a mixing bowl, whisk together the brown sugar, maple syrup, melted butter, egg, vanilla extract, cinnamon, and salt until smooth. Stir in the chopped pecans.
**Fill the Phyllo Shells:**
Spoon the pecan mixture into the phyllo shells, filling each one generously but not overflowing.
**Bake:**
Bake the filled shells for 12-15 minutes, or until the filling is set and the shells are golden brown.
**Cool and Serve:**
Allow the tarts to cool slightly before serving. Enjoy them warm or at room temperature