Cook the Noodles: First, cook your lo mein noodles according to the package directions. Once they're done, drain them and rinse them with cold water. This stops them from sticking together.
Make the Sauce: In a small bowl, whisk together the soy sauce, hoisin sauce, sesame oil, honey, rice vinegar, cornstarch, ground ginger, garlic powder, and red pepper flakes (if using). Set this aside. This sauce is the heart of the dish, so make sure everything is well combined.
Cook the Turkey: Heat the olive oil in a large skillet or wok over medium-high heat. Add the ground turkey and cook it until it's browned, breaking it up with a spoon as it cooks. This should take about 5-7 minutes. Make sure there are no pink bits left.
Add the Vegetables: Add the sliced bell peppers, julienned carrot, and sliced mushrooms to the skillet. Cook for about 3-5 minutes, or until the vegetables are slightly softened but still have a bit of crunch.
Combine Everything: Add the cooked noodles and the sauce to the skillet with the turkey and vegetables. Toss everything together until the noodles and vegetables are evenly coated with the sauce. The sauce will thicken as it heats up.
Simmer: Let everything simmer for a couple of minutes, allowing the flavors to meld together. Give it a good stir now and then.
Garnish and Serve: Remove from heat and garnish with chopped green onions. Serve hot and enjoy!