Preparation

• Arrange a rack in the middle of the oven and heat the oven to 375°F. Line a rimmed baking sheet with parchment paper.
• Finely chop ½ medium yellow onion and 2 garlic cloves. Place both in a large bowl. Add 1 pound ground beef, ½ cup panko breadcrumbs, 1 large egg, 2 tablespoons sweet chili sauce, 1 tablespoon oyster sauce, 1 tablespoon soy sauce, 1 teaspoon toasted sesame oil, 1 teaspoon ground ginger, and ¼ teaspoon black pepper. Mix together with your hands until evenly combined.
• Using wet hands or a cookie scoop, portion the mixture into about 26 meatballs (about 1 ½ tablespoons each). Roll each one between your hands to form a smooth ball. Place on the baking sheet, spacing them evenly apart.
• Bake for 15 minutes. Meanwhile, make the glaze: Place 3 tablespoons sweet chili sauce, 1 tablespoon ketchup, 1 tablespoon rice vinegar, 1 tablespoon oyster sauce, 1 tablespoon soy sauce, 1 tablespoon honey, and 1 teaspoon toasted sesame oil in a small saucepan. Bring to a simmer over medium-low heat, stirring occasionally. Simmer until slightly thickened and syrupy, 3 to 5 minutes. Remove the saucepan from the heat.
• Remove the meatballs from the oven and brush the meatballs with the glaze, using it all.
• Return the meatballs to the oven. Bake until cooked through, 5 to 7 minutes more. Sprinkle with 1 tablespoon toasted sesame seeds.