Prepare the sauce by mixing regular soy sauce, dark soy sauce, oyster sauce, brown sugar, crushed red pepper, toasted sesame oil, chicken stock, and cornstarch. Whisk until smooth and set aside.

Marinate the beef by slicing it against the grain into thin strips and combining it with salt, cornstarch, and baking soda. Let it rest for 20-30 minutes.

Cook the udon noodles in boiling water according to package instructions, draining them 1-2 minutes early to keep them firm. Toss with oil to prevent sticking.

Stir-fry the marinated beef in a hot wok with vegetable oil until golden brown. Remove and set aside.

In the same wok, stir-fry ginger, garlic, and Thai red chilies until fragrant. Add green bell pepper and carrots, cooking until just tender.

Combine the sauce with the vegetables in the wok, then add udon noodles and crispy beef, tossing everything together until heated through.

Serve garnished with green onions and sesame seeds. Enjoy warm!