Begin by placing the lo mein (or substitute) in boiling water. Cook just shy of al dente (about 1–2 minutes less than the package suggests), because they’ll continue cooking in the pan later. Drain and set aside.
In a bowl, whisk together beef broth, soy sauce, brown sugar, hoisin sauce, cornstarch, and about three-quarters of the minced garlic and ginger (reserve the rest). Having the sauce ready helps keep things moving quickly once the beef starts cooking.
Preheat your skillet or griddle to medium (around 400°F if using one). Spread the ground beef in small chunks and let it sear untouched for 2-3 minutes—this adds deep flavor through browning. Once the beef is half-cooked and still a little pink, add the sliced green onion whites and sauté until almost fully cooked.
To the same cooking surface, add a splash of oil, then the remaining garlic and ginger. Let them toast briefly without burning. Add the drained noodles and spread them out to get a light char for 1-2 minutes. Then add the cooked beef and slowly pour in your sauce, tossing everything together until it thickens and coats the noodles beautifully. Finish by sprinkling the green onion tops and serve immediately.