Heat the oven to 350°F (175°C). Fit the pie crust into a 9-inch pie dish, crimp the edges, and prick the bottom all over with a fork. Line with parchment and pie weights or dried beans and blind-bake for 10 minutes. Remove the weights and parchment and set the crust aside.
Whisk the pumpkin puree, granulated sugar, eggs, evaporated milk, vanilla, cinnamon, ginger, nutmeg, cloves, and salt in a large bowl until completely smooth.
Pour the pumpkin filling into the warm crust and smooth the top. Bake at 350°F (175°C) for 25 minutes, until the edges are just beginning to set.
While the pie bakes, whisk the brown sugar, maple syrup, melted butter, egg, vanilla, and salt in a medium bowl until smooth. Stir in the chopped pecans.
Carefully spoon the pecan mixture over the hot pumpkin layer and spread it gently to the edges. Arrange the pecan halves on top in a decorative pattern.
Return the pie to the oven and bake 25–30 minutes more, until the pecan topping is bubbling and golden and the center jiggles only slightly when you nudge the pan. The filling will firm up as it cools.
Cool the pie on a wire rack for at least 2 hours before slicing. Serve warm or at room temperature, with whipped cream or vanilla ice cream if you like.