Make the pastry dough: In a large bowl, mix the flour, butter, and salt. Using a pastry cutter, cut the butter into the flour until the mixture resembles coarse breadcrumbs.

In a small bowl, whisk together the egg and ice water. Add to the flour and, using your hands, bring the dough together until it just barely hangs together. Do not overmix. If it’s too dry, add more water a tablespoon at a time, until it just comes together.

Turn the dough out onto a lightly floured work surface and gently knead for 2 minutes. Shape the dough into a disc, wrap with plastic wrap, and refrigerate for at least 30 minutes and up to 3 days.

Meanwhile, preheat the oven to 350°F (180°C).

On a lightly floured work surface, use a rolling pin to roll out the dough into a 12-inch circle, about ⅛ inch thick. Lay the dough in a 9-inch pie plate and gently press it against the edges of the dish. Prick small holes across the surface of the dough with a fork. Trim excess dough and crimp the edges.

Make the filling and bake: In a large bowl, whisk together the maple syrup, egg, brown sugar, and cream until smooth. Pour the filling into the pie shell. Spread the pecans evenly over the filling.

Bake until the filling is set, about 35 minutes. Transfer to a wire rack and let cool completely before serving. Store leftover pie, wrapped in plastic wrap, on the counter for up to 2 days.