If using meat, marinate it for at least 15 minutes in a mixture of 1 tablespoon soy sauce and 1 teaspoon cornstarch. If using tofu, press it well to remove excess water.

If using frozen udon, thaw them. If using dried udon, cook according to package directions until al dente. Be careful not to overcook. Drain and rinse the noodles with cold water.

In a small bowl, whisk together the soy sauce, oyster sauce, mirin, sugar, sesame oil, minced garlic, and grated ginger. Set aside.

Heat 1 tablespoon of vegetable oil in a large wok or skillet over medium-high heat. Add the marinated meat (or tofu) and stir-fry until cooked through. Remove from the wok and set aside.

Add the remaining 1 tablespoon of vegetable oil to the wok. Add the onion, carrot, and bell pepper and stir-fry for 2-3 minutes, until slightly softened. Add the mushrooms and cabbage and continue to stir-fry for another 2-3 minutes, until the vegetables are tender-crisp.

Add the cooked protein (or tofu) back to the wok with the vegetables. Pour in the prepared Yaki Udon sauce and bring to a simmer. Stir in the cornstarch slurry (cornstarch mixed with water) to thicken the sauce.

Add the cooked udon noodles to the wok and toss everything together until the noodles are evenly coated in the sauce.

Garnish with chopped green onions and sesame seeds (if using). Serve immediately and enjoy!