Bring a pot of water to a boil and cook the noodles, without seasoning, as directed on package. Drain once finished.
While cooking, add all ingredients from soy sauce to red pepper flakes (if adding) to a bowl. Whisk together and set aside.
Right before noodles are complete, add sauce ingredients to a skillet over medium low heat. Let heat through, then add drained noodles and toss until very well combined.
Serve in bowls and garnish with green onions and sesame seeds if desired.
Note: This is not served with a broth, but if you like noodles with broth, then you can add a mushroom or vegetable stock when adding the sauce.
