In a small bowl, combine the hot boiled water, Beef Better Than Bouillon, and brown sugar. Stir until completely dissolved, then mix in the soy sauce to create a rich, savory-sweet sauce. Set aside.

Heat a large skillet or wok over medium-high heat and drizzle in sesame oil. Add the sliced beef and cook for 3–4 minutes, stirring occasionally, until browned and caramelized. Remove the beef from the pan and set aside.

In the same skillet, add a little more sesame or olive oil if needed. Sauté the sliced onions until golden and fragrant, about 3 minutes, then remove and set aside. Add the carrots to the skillet and cook until slightly tender. Stir in the broccoli and continue cooking for another 2–3 minutes until just softened but still vibrant in color. Return the onions to the pan and press in the garlic, stirring to blend the flavors together.

Add the cooked beef back to the skillet and pour the prepared sauce over the mixture. Toss everything to coat evenly and allow it to simmer for about 2 minutes, letting the flavors meld and the sauce thicken slightly.

Add the cooked lo mein noodles to the pan and toss well to combine the beef, vegetables, and sauce. Continue tossing for 1–2 minutes until everything is evenly mixed and heated through.

Transfer to a large serving dish and serve immediately while hot. Each bite delivers a perfect balance of tender beef, crisp vegetables, and flavorful noodles coated in a glossy, savory-sweet sauce.