Preheat your oven to 450°F (230°C) and line a baking sheet with parchment paper or foil.

In a large bowl, combine ground beef, green onions, ginger, garlic, salt, and pepper. Mix well and shape into meatballs.

In a separate bowl, toss broccoli florets with olive oil, salt, and pepper, then spread on the baking sheet.

Bake meatballs and broccoli in the oven for about 15 minutes until cooked through and tender.

Meanwhile, heat vegetable oil in a skillet and add soy sauce, brown sugar, garlic, ginger, water, vinegar, and red pepper flakes. Cook for about 10 minutes until thickened.

Mix cornstarch with water, then add to sauce until thickened, then remove from heat.

Add baked meatballs to the sauce and toss to coat.

Serve meatballs warm with broccoli, garnished with extra green onions and sesame seeds, if desired.