1. Place the onion, red and green peppers, and mushrooms in a medium skillet or saucepan and sauté over medium-high heat for 7 to 8 minutes, or until the onion is translucent. Add water 1 to 2 tablespoons at a time to keep the vegetables from sticking to the pan.
2. Add the cauliflower and cook for 5 to 6 minutes, or until the florets are tender.
3. Add the salt, pepper, turmeric, cayenne, garlic, soy sauce, and nutritional yeast (if using) to the pan, and cook for 5 minutes more, or until hot and fragrant.