First, cook the udon noodles according to the package instructions. If using fresh noodles, they will only need about 2 minutes of cooking time whereas dried noodles need about 8 minutes. Once cooked, strain and set aside.
While the noodles are cooking, prep the veggies and sauce. Slice the peppers, cabbage, and carrot into thin strips and set aside.
To make the sauce, mix together the dark soy sauce, vegan oyster sauce, mirin, brown sugar, and optional gochujang. Then, set aside.
Add the sesame oil to a wok and turn on the heat. Once the oil is hot, add the peppers, carrots, cabbage, and snow peas to the wok. Saute for about 5 minutes until the cabbage decreases in volume and the veggies are beginning to char.
Next, add the cooked udon noodles and the stir fry sauce to the wok. Mix together until the noodles and veggies are coated in the sauce. Then, continue cooking for 3-5 minutes until the sauce is sticky.
Remove the yaki udon from the heat and serve immedaitely. To garnish, top with optional sesame seeds and/or chopped green onions. Enjoy!