Preheat your oven to 400°F.

In a large bowl, combine ground beef, breadcrumbs, Parmesan cheese, green onions, egg, garlic, salt, black pepper, ginger, and red pepper flakes (if using). Mix until well combined.

Form the mixture into 1-inch meatballs and place them on a baking sheet lined with parchment paper.

Bake for 20-25 minutes or until cooked through and browned.

While the meatballs are baking, prepare the sauce. In a small saucepan over medium heat, combine soy sauce, brown sugar, cornstarch, and water. Stir until the mixture thickens, about 2-3 minutes. Remove from heat.

Once the meatballs are done, heat vegetable oil in a large skillet over medium heat. Add the baked meatballs and pour the sauce over them. Toss to coat and cook for an additional 2-3 minutes until heated through.

Serve warm, garnished with extra green onions if desired.