Boil macaroni until just al dente. Drain and set aside.
In a bowl, combine ground beef with 1 tbsp Maggi, ½ tbsp fish sauce, sugar, and chicken bouillon. Mix well and let sit for 10–15 minutes.
Heat 2 tbsp oil in a large pan or wok. Add onions and sauté until fragrant. Add marinated beef and stir-fry on high heat until about 80% cooked.
Add cooked macaroni to the pan. Pour in the remaining Maggi and fish sauce, tossing well so the pasta absorbs all the flavor. Add mixed vegetables (if using) and stir-fry for another 2–3 minutes.
Season with black pepper, taste, and adjust if needed. Serve hot — optionally topped with a fried egg or with sliced cucumbers and pickled veggies on the side for that classic Vietnamese balance.
