In a pot of boiling water add the cauliflower and carrots. Turn off the heat and let the vegetables stand for about 2 minutes. Drain and set aside.
Combine all the sauce ingredients and mix well to dissolve he cornstarch or arrowroot. Set aside.
In a large wok or heavy skillet, heat half the oil over high heat.
Swirl the oil around to coat the bottom of the pan. Add the garlic, ginger and scallions and stir-fry for 30 seconds. Add the chicken and continue to stir-fry for 4 or 5 minutes or until chicken is cooked through.
Add the cauliflower and carrots and continue to stir-fry for 2 to 3 minutes to coat the vegetables with the garlic mixture.
Give the sauce another quick stir and add to the pan. Cook for 1 to 2 minutes until sauce coats everything and is slightly thickened.