In a medium-sized bowl, add soy sauce, brown sugar, cornstarch, ginger, garlic and red pepper then whisk until brown sugar and cornstarch have dissolved. Add thinly sliced chicken and stir, ensuring each piece is coated with marinade. Cover and refrigerate for 10 minutes.

Place a wok or large skillet over medium-high heat and add sesame oil. Add sliced onion and grated carrots and cook, stirring frequently, for approximately 4 minutes until onions become soft and translucent.

Add frozen stir-fry vegetables and cook 5–6 minutes just until hot. At this point, they should also be crisp and tender. Transfer vegetables to a plate, cover loosely to keep warm and set aside.

Return skillet or wok to heat and add all of the chicken including the marinade. Stir constantly until sauce is thick and chicken is completely cooked through. Depending upon how thin the chicken has been sliced, it should take between 3–5 minutes. Add water 2 Tbsp at a time if the sauce becomes too thick. You want it thin enough to coat all the veggies.

Add vegetables back into the pan, stir to coat with sauce and continue cooking only until veggies reach desired tenderness. Remove from heat, garnish with onions, sprouts or cashews if you like. Serve immediately over a bed of steamed rice or noodles.