Cook the noodles according to package instructions.
Heat oil in a wok or large skillet over medium-high heat.
Add the garlic, onion, carrot, and bell pepper. Stir-fry for 2-3 minutes.
If using protein, add it to the wok and stir-fry until cooked through.
Add the cooked noodles to the wok.
In a small bowl, mix together the hoisin sauce, soy sauce, and sesame oil. Add the sauce to the wok and toss everything together, adding a bit of water to thin the sauce if needed.
Serve hot.
