Heat the oil in a large, heavy saucepan and sauté the mushrooms, carrots, and onions until lightly browned. Optional: Water sauté the vegetables.
Add the potatoes, vegetable broth, parsley, basil, red pepper, salt, and black pepper, and bring to a boil.
Cut in the vegan margarine with a pastry cutter or knives.
Stir in enough plant-based milk to make a stiff but pliable dough.