Step 1

Line a rimmed baking sheet with kitchen parchment and mist with cooking spray; set aside. In a 12-inch nonstick skillet over medium-high, combine the sake, mirin, soy sauce, smashed garlic and bruised ginger. Bring to a boil and cook, stirring often, until reduced to ⅓ cup, 6 to 8 minutes. Remove and discard the garlic and ginger; transfer the mixture to a small bowl. Rinse out and dry the skillet.

Step 2

In a large bowl, combine the chicken, the grated garlic, the grated ginger, ¼ cup scallions, the panko, egg white, sesame oil and ¼ teaspoon pepper. Using your hands or a silicone spatula, vigorously stir and knead the mixture until well combined and sticky. Using lightly oiled hands, divide the mixture into 16 portions (about 2 tablespoons each), form each into a ball and place on the prepared baking sheet. Lightly press each ball to slightly flatten it into a 1- to 1¼-inch round.

Step 3

In the same skillet over medium-high, heat the neutral oil until shimmering. Place the meatballs in the skillet, reduce to medium and cook until lightly browned on the bottoms, about 4 minutes. Flip each meatball and add the sake-soy mixture; continue to cook, occasionally turning the meatballs and basting them with the sauce, until the centers reach 160°F and the exteriors are glazed, 5 to 7 minutes; reduce the heat to medium if the soy mixture is reducing too quickly.

Step 4

If desired, transfer the meatballs and glaze to a serving dish. Sprinkle with the remaining scallions.