In a large mixing bowl, whisk together the brown sugar, cornstarch, pumpkin pie spice, cinnamon, nutmeg and salt. Add 1-2 tablespoons of the non-dairy milk, stirring until a thick paste forms. Slowly pour in the remaining non-dairy milk, whisking continuously to prevent clumping. Stir in the pumpkin puree, maple syrup and vanilla extract.
Place your 9" pie dough in a pie dish. If you're using the oil pie crust recipe, I recommend avoiding any fancy edges. It'll be easiest if you just make a flat, simple edge.
Pour the pumpkin mixture into the unbaked pie crust. Smooth into an even layer with a spatula. Place the pie on the middle rack of the oven. Bake at 375F for 45-55 minutes. Cover edges with tin foil or a pie shield if baking too quickly.
The pie is cooked when the edges are firm and the center is still a little jiggly, but not liquid. Remove from the oven and let cool to room temperature, about an hour. After cool, refrigerate for 3-4 hours, until chilled through.
Once chilled, slice and enjoy with non-dairy whipped topping and a drizzle of maple syrup.
Milk: I usually use unsweetened, unflavored soy milk but almond and oat milk should also work.
Pumpkin puree: This is not the same as pumpkin pie filling. One 15 ounce can of pumpkin puree usually has ~2 cups pumpkin.
Pie dish: The pie takes longer to bake and set depending on the dish you use. It is done in about 50 minutes using a thin metal pie dish (the disposable kind). Ceramic or glass may take 5-10 minutes longer.
If you use a store-bought crust, follow the instructions on the packaging to bake the pie.
Can I make the pie filling in advance? You can make the filling one day in advance. Mix the filling together per the recipe instructions, cover and refrigerate. Remove from the fridge and use according to recipe instructions.
How long does this keep? For best quality, store covered in the fridge for no longer than 3-4 days.