1. Preheat your oven to 350°F (175°C). If you have a baking sheet, place your pie pan on it to catch any drips.
2. Make the crust: In a large bowl, whisk together the flour and salt. Add the cold, cubed butter. Using a pastry cutter or your fingers, work the butter into the flour until the mixture resembles coarse crumbs with pea-sized pieces.
3. Slowly add ice-cold water, one tablespoon at a time, stirring gently until the dough just comes together. Be careful not to overwork it. Form the dough into a disk, wrap in plastic, and chill for at least 30 minutes.
4. While the dough chills, toast the walnuts in a dry skillet over medium heat for 3-5 minutes, stirring frequently until fragrant. Remove from heat and set aside.
5. On a lightly floured surface, roll out the chilled dough into a 12-inch circle. Transfer it carefully to a 9-inch pie pan. Trim and crimp the edges. Chill again for 10 minutes to prevent shrinking.
6. Prepare the filling: In a medium bowl, whisk together the maple syrup, brown sugar, eggs, melted butter, vanilla extract, and cinnamon until smooth and combined.
7. Stir in the toasted walnuts, ensuring they’re evenly coated with the syrup mixture.
8. Pour the filling into the prepared crust, spreading it out evenly. Bake in the preheated oven for 50-60 minutes, or until the filling is set around the edges but still slightly jiggly in the center. A toothpick inserted near the center should come out mostly clean.
9. Remove the pie from the oven and allow it to cool completely on a wire rack. The filling will continue to set as it cools.
10. Once cooled, slice and serve. This pie is especially delicious the day after baking when the flavors have melded beautifully.

From my experience, chilling the dough twice and toasting the walnuts makes a huge difference—a lesson learned after a few early baking experiments where the crust shrunk or the nuts tasted dull. Patience here really pays off.