1. 1. In a wok or large skillet, heat oil over high heat.

2. 2. Add thinly sliced beef and stir-fry until browned, about 3-4 minutes.

3. 3. Add chopped vegetables (such as bell peppers, broccoli, and carrots) and stir-fry for another 2-3 minutes.

4. 4. In a small bowl, mix soy sauce, garlic, ginger, and brown sugar.

5. 5. Pour the sauce over the beef and vegetables, stirring to combine.

6. 6. Cook for an additional 2-3 minutes until the sauce thickens slightly.

7. 7. Serve hot over rice or noodles.