Cook potato and carrot in a pot of boiling salted water until tender, about 10 minutes, drain, rinse and set aside.
Put stock and tamari in a small saucepan and bring to a boil over medium-high heat, reduce to low and whisk in the cornstarch-water mixture, simmer 2-3 minutes, stirring until thickened, remove from heat and set aside.
Heat the olive oil in a medium-size skillet over medium heat.
Add the onion, cover and cook until softened, about 5 minutes.
Add the onion to the potatoes and carrots and mix in the tofu, corn and peas.
Preheat oven to 350°F.
For the crust, incorporate the salt into the flour, add the corn oil and with 2 butter knives cut the oil into the flour until crumbly and well incorporated.
Add the water and mix until it forms a ball. (if it's too crumbly, add water by the tablespoonful until it comes together. different climates affect flour differently.).
Divide the crust in two and on a lightly floured surface, roll out each ball until it is slightly larger than a 2-quart casserole dish.
Place one half into the casserole dish, and put the vegetables on top.
Place the second crust over the vegetables and crimp the edges.
Bake until the filling is hot and bubbly and the crust is browned, about 45 minutes.
Let rest for 5 minutes before serving.
p.s. someone asked a question whether to use silken or waterpacked. waterpacked/chinese-style is ideal, but it may still work if all you have is silken. or go ahead and omit the tofu altogether. it's an adaptable recipe.