In a large skillet, heat sesame oil over medium-high heat. Add ground beef and cook for 5-7 minutes, stirring until browned. Drain excess fat and mix in soy sauce, brown sugar, garlic, and ginger.

Add diced bell pepper, sliced carrot, and chopped bok choy. Stir-fry for 3-4 minutes until vegetables are tender yet crisp.

Turn heat down to low and let the mixture simmer for 2-3 minutes. Optionally, sprinkle in additional soy sauce or sriracha.

Prepare cooked rice according to package instructions. Divide rice into bowls and top with the beef and vegetable mixture.

Garnish with chopped green onions and drizzle with sesame oil. Serve hot.