Preheat your oven to 375°F (190°C). Roll out the pie dough and fit it into a 9-inch pie dish, crimping the edges as desired.

In a large mixing bowl, whisk together the pumpkin puree, eggs, 1/2 cup brown sugar, maple syrup, heavy cream, vanilla extract, bourbon, pumpkin pie spice, and salt until the mixture is completely smooth.

Pour the pumpkin filling into the prepared pie crust, smoothing the top with a spatula.

Place the pie in the oven and bake for 40 minutes.

While the pie bakes, prepare the crumble topping. In a small bowl, mix the chopped pecans, 1/4 cup brown sugar, flour, and cold cubed butter using your fingers until the mixture resembles coarse crumbs.

After the 40-minute mark, carefully remove the pie from the oven and sprinkle the pecan crumble evenly over the top of the custard.

Return the pie to the oven and bake for an additional 15-20 minutes, or until the filling is set around the edges but still slightly jiggly in the very center.

Remove from the oven and place on a wire rack to cool completely for at least 4 hours to allow the filling to set firm before slicing.