Preheat your oven to 400 degrees F. Line a large rimmed baking sheet with foil and set a wire rack on top. Spray the rack lightly with nonstick cooking spray. The rack lifts the meatballs off the pan so heat circulates underneath and they brown all around without flipping.

Start your rice according to package directions so it is ready when the meatballs finish. For stovetop rice, combine 2 cups dry rice with 3 1/2 cups water in a medium pot. Bring to a boil, reduce heat to low, cover, and cook for 18 minutes. Remove from heat and let it steam covered for 5 minutes.

In a large mixing bowl, combine the ground beef, breadcrumbs, egg, 2 cloves of the minced garlic, salt, and pepper. Mix with your hands just until everything is evenly combined. Do not overwork the meat or the meatballs will be dense. The mixture should hold together when pressed.

Portion the meat mixture into 20 meatballs, about 1 1/2 tablespoons each. Roll each one between your palms into a smooth ball and place it on the wire rack. They should all fit on one standard baking sheet with a little space between them.

Bake for 18 minutes. The meatballs are done when they are browned on the outside and register 165 degrees F on an instant-read thermometer at the center. They will look set and firm, not pink or soft.

While the meatballs bake, make the teriyaki sauce. In a medium saucepan over medium heat, combine the soy sauce, honey, rice vinegar, grated ginger, sesame oil, and the remaining clove of minced garlic. Stir and bring the mixture to a gentle simmer, about 3 minutes.

In a small bowl, stir together the cornstarch and cold water until smooth. Pour the slurry into the simmering sauce while stirring constantly. Cook for 1 to 2 minutes until the sauce thickens to a glossy, coat-the-spoon consistency. Remove from heat.

Transfer the hot baked meatballs directly into the saucepan and fold gently to coat them all in the teriyaki glaze. Serve immediately over steamed rice. Garnish with sesame seeds and sliced green onions.