Preheat the oven to 400 °F (204 °C) and lightly grease a rimmed baking sheet.
In a bowl combine the ground beef with the onion, panko, garlic powder and soy sauce. Mix until the ingredients are just combined.
1 pound ground beef, ½ onion, ½ cup panko breadcrumbs, 1 teaspoon garlic powder, 2 tablespoons low-sodium soy sauce
Use a medium cookie scoop (or 2 tablespoons) and scoop the beef mixture and shape into a ball. Place on the prepared baking pan and repeat the process with the rest of the meatballs. Spray the tops with a little bit of oil.
Bake for 15 to 18 minutes or until cooked through and internal temperature reads 160 °F (71 °C). Remove from the oven.
While the meatballs are baking, prepare the sauce. In a medium saucepan over medium-low heat, stir together the water, brown sugar, soy sauce, fish sauce, minced garlic, and red pepper flakes (if using). Cook, stirring constantly for 5 minutes or until the sugar is caramelized and the sauce is thick and sticky.
⅓ cup water, ⅓ cup brown sugar, ¼ cup low-sodium soy sauce, ½ tablespoon fish sauce, 2 cloves garlic, Red pepper flakes
Transfer the baked meatballs to the sauce and toss to coat. Serve with white rice and garnish with sliced scallions and sesame seeds.
Notes
If you want your sauce to be thicker, you can mix in 1 tablespoon of cornstarch with 2 tablespoons of water.