In a small mixing bowl, combine all the sauce ingredients. Mix well and set aside.
Heat cooking oil over medium high, add shrimp and stir fry until both side of the shrimp change color. Remove from the pan.
Add cooking oil to the same pan, stir fry onion and garlic for 2 minutes than add carrot and mushroom and cook until the carrot are soften. Stir occasionally.
Add udon noodle, cooked shrimp, and sauce mixture then toss them together until well combined. Add scallion and stir for 1 minute.
Place yaki udon to a serving plate and serve immediately. Enjoy!