firm tofu (14 oz / 400g), pressed to remove excess water • cabbage, finely shredded • carrots, julienned (cut into thin matchsticks) • green beans, finely chopped • shiitake or button mushrooms, finely chopped • small onion, finely chopped • garlic, minced • soy sauce (or tamari for gluten-free) • sesame oil (optional for extra flavor) • vegan oyster sauce (optional) • Salt and pepper, to taste • cornstarch (optional, for binding) •