In a large bowl, combine the pumpkin, egg, milk, sugar, maple syrup, pie spice and salt and whisk until smooth.
Preheat your oven to 425°F (210°C).
Pour filling into crust. If using decorative shapes around the crust, layer them around the edge of the filled pie.
Brush the finished crust with egg wash.
Bake at 425°F (210°C) for 15 minutes. Reduce heat to 350°F (180°C) and bake for 20-25 minutes longer or until crust is golden brown and top of pie is set (cover edges with foil during the last 15 minutes to prevent over browning if necessary).
Cool on a wire rack for 1 hour. Refrigerate overnight or until set. Keep refrigerated for up to 3 days.