Preheat the oven to 350°F and place a rack in the middle position.
Fit the unbaked pie crust into a pie dish, pressing it into the sides and trimming any excess dough; crimp the edges as desired.
In a medium bowl, add 1/2 cup dark brown sugar, 1/2 cup brown rice syrup or corn syrup (your choice), 2 tablespoons melted unsalted butter, 2 large eggs, 1 teaspoon vanilla extract, and 1/4 teaspoon kosher salt.
Whisk those ingredients together until the sugar is dissolved and the mixture is smooth and uniform.
Stir in 1 1/2 cups raw pecans until they are evenly coated with the filling.
Pour the pecan filling into the prepared crust, spreading the pecans into an even layer.
Bake on the middle rack for 45 minutes, until the pie edges are set and the center is mostly set with a slight jiggle.
Remove the pie from the oven and let it cool completely on a wire rack before slicing and serving.