In a medium bowl, combine soy sauce, rice vinegar, sesame oil, and cornstarch to create a smooth marinade. Add the boneless, skinless chicken breasts, ensuring they’re coated evenly. Cover the bowl and let the chicken marinate in the refrigerator for at least 15 minutes.

While the chicken is marinating, wash and chop the scallions into thin slices, using both the green and white parts for color and flavor. Mince a few cloves of garlic and a small piece of fresh ginger. Set these aromatic ingredients aside.

In a large skillet or wok, pour in a couple of tablespoons of vegetable oil and heat over medium-high heat until shimmering, about 2-3 minutes.

Carefully add the marinated chicken breasts to the skillet in a single layer. Cook for about 5-7 minutes on each side until golden brown and fully cooked through, reaching an internal temperature of 165°F (75°C).

Once the chicken is cooked, remove it from the skillet and set aside. In the same skillet, add minced garlic, ginger, and chopped scallions, stirring for 2-3 minutes until fragrant.

If there is leftover marinade, pour it into the skillet with the sautéed aromatics. Bring to a gentle simmer, allowing it to thicken for about 2-3 minutes.

Return the cooked chicken to the skillet, tossing to coat in the sauce. Let it rest for a couple of minutes before slicing into strips. Serve over white rice or noodles, garnished with extra scallions.