In a small bowl, mix hot water with beef bouillon and brown sugar, stirring until dissolved. Add soy sauce and set aside.

Heat sesame oil in a skillet, then cook beef strips until browned. Remove from the skillet and set aside.

In the same skillet, sauté the onion until golden. Add the carrots and cook until they begin to soften. Stir in the broccoli and cook for about 3 minutes. Add minced garlic and cook for another minute.

Return the cooked beef to the skillet with the vegetables. Pour the sauce over everything and let it simmer for 2 minutes.

Add the cooked lo mein noodles to the skillet, tossing everything together until evenly coated.

Serve immediately and enjoy!