Make the Pastry Crust: Combine flour and salt. Cut in cold butter until crumbly. Add ice water, 1 tbsp at a time, until dough forms. Shape into a disk, wrap, and refrigerate for 30 minutes.
Prepare Tart Shells: Roll out dough, cut into circles, and press into a muffin tin.
Make the Filling: Whisk brown sugar, maple syrup, melted butter, egg, vanilla, and salt. Stir in pecans (and raisins, if using).
Assemble Tarts: Fill tart shells 3/4 full with the filling.
Bake and Cool: Bake at 375°F (190°C) for 15-20 minutes until golden. Cool in the tin for 5 minutes, then transfer to a wire rack.