For the crust: In a large bowl, whisk together the gluten-free flour, almond flour, powdered sugar, and salt. Cut in the cold butter until the mixture resembles coarse crumbs. Stir in the egg yolk and 2 tablespoons cold water. Add more water if needed to form the dough. Wrap in plastic and refrigerate for 30 minutes.

1. Roll out the dough: Once chilled, roll the dough between parchment paper and press it into a 9-inch pie pan. Trim the excess dough and prick the bottom of the crust. Preheat the oven to 350°F (175°C) and bake for 8-10 minutes until lightly golden.
2. For the filling: Whisk together the brown sugar, maple syrup, melted butter, eggs, vanilla extract, salt, and bourbon (if using) until well combined. Stir in the pecans.
3. Assemble the pie: Pour the filling into the pre-baked crust, spreading the pecans evenly. Bake for 40-45 minutes, until the filling is set and slightly puffed. Cover the edges with foil if they brown too quickly.
4. Cool and serve: Let the pie cool for 2 hours to allow the filling to set. Slice and serve, optionally topped with whipped cream or vanilla ice cream.