1. Preheat your oven to 375°F. Line a baking sheet with parchment paper.

2. In a large mixing bowl, combine the chopped onion, garlic, ground beef, panko breadcrumbs, egg, sweet chili sauce, oyster sauce, soy sauce, sesame oil, ginger, and black pepper.

3. Mix gently with your hands until everything is evenly incorporated. Avoid overmixing.

4. Using slightly damp hands or a small scoop, shape the mixture into 24 to 26 meatballs, about 1 1/2 tablespoons each.

5. Arrange the meatballs on the prepared baking sheet, leaving a little space between each one.

6. Bake for 15 minutes.

7. While the meatballs bake, prepare the glaze. In a small saucepan, combine the sweet chili sauce, ketchup, rice vinegar, oyster sauce, soy sauce, honey, and sesame oil.

8. Cook over medium-low heat, stirring occasionally, until the mixture becomes slightly thickened and glossy, about 3 to 5 minutes. Remove from the heat.

9. Remove the meatballs from the oven and brush them generously with the glaze.

10. Return the meatballs to the oven and bake for an additional 5 to 7 minutes, or until fully cooked through.

11. Transfer to a serving platter and sprinkle with toasted sesame seeds before serving.