In a small mixing bowl, whisk together brown sugar, soy sauce, ginger, garlic, sesame seeds and cornstarch. Set aside.
In a large skillet, heat up olive oil. Add chicken and season with salt and pepper. Cook until no longer pink. Add carrots, peppers and mushrooms. Cook until peppers are tender. Add spinach and cook, stirring, until spinach is wilted. Add cooked noodles to the skillet. Stir. Add sauce and cook, stirring often, until everything is heated up.
Serve garnished with chopped green onions or toasted sesame seeds.
Notes
If you don't have fresh ginger on hand, feel free to use ground ginger. Of all the vegetables you can use in this dish, I would say definitely go with mushrooms and peppers. They add serious flavor. If you are not a fan of spinach (or know that your family won't like it), skip it and maybe use snow peas. It is recommended to use lo mein egg noodles in this dish but if you can't find them - simply use spaghetti noodles. They will work just fine! You can use any meat you like (beef, pork, chicken or shrimp) or keep it simple with veggies. Use any blend you like: carrots, cabbage, snow peas, edamame beans, peppers, mushrooms, spinach.