Make or buy a vegan pastry crust and form it to a 9-inch pie dish.
Bake the pie crust for 10 minutes.
While the crust is baking, add the pumpkin, coconut milk, brown sugar, pie spice, vanilla, and salt to the blender and blend for about 30 seconds.
Taste and make sure the sweetness and spices are to your liking.
Add the chickpea flour and blend again for about 30 seconds until it is all incorporated. (Don't taste it after this! Chickpea flour tastes horrible until it's fully cooked).
Pour the filling into the pie crust that has been baked for 10 minutes.
Bake the pie at 350°F (177°C) for 1 hour and 15 minutes. (The top of the pie should look slightly dry, and there may be small cracks at the sides of the pie.
Allow cooling at room temperature for 1-hour then place in the fridge for a minimum of 3 more hours before cutting. It will be best if it is allowed to set in the refrigerator overnight.
Notes
Pour the pie filling into the pie shell near the oven, so you don't have far to walk with it. It will be very runny and easy to spill.
Don't cook hotter than 350°F (177°C). This pie needs to cook long and slow to ensure it has cooked the whole way through.
Make sure to cook the pie for the full 75 minutes. Remember, the chickpea flour tastes awful if it is not thoroughly cooked through.
Store in the fridge uncovered until fully cooled. Don't cover until all steam has left the pie.
It is best after it has cooled overnight in the fridge. (It's still delicious the first day, but just firmer and denser once it has chilled).