In a small saucepan, melt the margarine and add the flour. Add the vegetable broth, soy sauce, garlic powder and onion powder, stirring frequently, until sauce thickens. Whisk in the vegetable oil and nutritional yeast.
Toss together the sauce and green beans in a casserole dish. Bake for ten minutes. Remove and sprinkle the French fried onions on top of the casserole. Bake for another ten minutes.
Scroll down for more meatless green bean casserole and more holiday green bean recipes to try.