In a large skillet or wok, heat over medium-high heat, and add ground beef. Cook for about 5-7 minutes until browned and no longer pink.

Add vegetable oil to the skillet, swirling to coat. Toss in chopped onion and sauté for about 5 minutes until soft and translucent.

Stir in minced garlic and cook for 1 minute until fragrant.

Add broccoli florets, sliced carrots, and sliced bell pepper to the skillet. Cook for 5-7 minutes until vegetables are tender-crisp.

In a bowl, whisk together soy sauce, cornstarch, and water until smooth.

Pour prepared sauce over the beef and vegetable mixture. Stir for about 2 minutes until sauce thickens.

Serve stir-fry over cooked rice or alternative.