01 - In a bowl, toss the chicken slices with cornstarch, salt, and black pepper until evenly coated.
02 - Heat vegetable oil in a large skillet or wok over medium-high heat. Add the chicken in a single layer. Cook for 2–3 minutes per side, until golden and cooked through. Remove chicken and set aside.
03 - In a small bowl, whisk together soy sauce, hoisin sauce, brown sugar, water, and cornstarch until smooth.
04 - In the same skillet, add a splash of oil if necessary, then add garlic and ginger. Sauté for 30 seconds until fragrant.
05 - Pour in the sauce mixture. Bring to a simmer and cook for 2–3 minutes, stirring frequently, until the sauce thickens.
06 - Return the chicken to the skillet and toss to coat in the sauce. Cook for 1–2 minutes more, until heated through.
07 - Stir in half of the sliced scallions.
08 - Serve immediately over steamed rice, garnished with remaining scallions and sesame seeds if desired.