Crust
in a food processor blend the flour and salt together. Add margarine and blend until it resembles coarse meal. Add the "milk" and blend until well combined or until dough forms. roll into two balls wrap and chill for at least one hour.
Filling
Preheat the oven to 350 F (180 C)
In a large saucepan, saute the onions and mushrooms in the olive oil until onions are translucent. Add the potatoes, celery, carrots, tamari, sage, thyme and stock. Bring to a boil, than reduce heat. Cover with lid and simmer for 4-6 minutes or until potatoes can be poked easily with a fork. Stir in the flour and simmer until sauce begains to thicken.
Roll out crust between two peices of parchment or waxed paper (dough is too sticky so if you don't use parchment be prepared for a lotta cussing)
place dough in a 9 in pie plate, fill and place top crust on. I don't do anything fancy, I just fold over the edges, I think this gives the pie a nice rustic look 
Bake for 20-25 minutes, let sit for 5 minutes before serving.
more or less from "La Dolce Vegan"
4
90
crust
2 cups all purpose or pastry flour
1 tsp salt
2/3 cup margarine cut into small pieces
4 Tbsp rice or soy milk
filling
1 medium onion, chopped
2 large portobello mushrooms, stems removed, cubed
6 button mushrooms, chopped
1 Tbsp olive oil
1 small potato, cubed
1 medium carrot, chopped
1 stalk of celery, chopped
2 Tbsp tamari
1/2 tsp dried thyme
1 tsp dried sage
3/4 cups vegetable stock
2 Tbsp flour