Directions:
1. Prepare the udon noodles according to the package.
2. In a small bowl, combine the OKAZU, rice wine vinegar, soy sauce, oyster sauce, brown sugar, garlic and ginger to make the sauce.
3. In a pan, add the oil and allow to heat up. Once hot, add the onions and saute on medium-high heat for 3-4 minutes. Afterwards, add the mushrooms and saute for 2 minutes. Add the bok choy to the pan and saute until the leaves start to wither. Add 1/2 of the sauce to the pan and mix well making sure to coat all the vegetables, and saute for another 2 minutes to thicken the sauce.
4. Add the udon noodles to the pan along with the remaining sauce and mix for about 2-3 minutes on the heat. Remove from the stove once the noodles are fully covered in the sauce, and garnish with the sesame seeds.