1. Thinly slice the chicken and coat evenly with cornstarch.
2. Heat vegetable oil in a pan over medium-high heat and fry the chicken in batches until browned and crispy. Set aside.
3. In the same pan, remove excess oil, then add minced garlic and ginger, cooking briefly until fragrant.
4. Add sesame oil, soy sauce, brown sugar, and water or chicken stock. Simmer until sugar dissolves.
5. Stir in the cornstarch slurry to thicken the sauce.
6. Return the fried chicken to the pan, add green onions, and toss everything to coat well.
7. If using, add optional vegetables for extra texture and cook until just tender.
8. Serve immediately over steamed rice or low-carb alternatives.