In a small bowl, mix together the light soy sauce, dark soy sauce, rice vinegar, cornflour, and sugar. Set aside.

Heat peanut oil in a wok or large frying pan over medium-high heat.

Add the diced chicken breast and stir-fry until browned and cooked through, about 5-6 minutes. Remove from the pan and set aside.

In the same pan, add a little more peanut oil if needed. Add the minced garlic, minced ginger, sliced red chilli, and Sichuan peppercorns. Stir-fry for about 1 minute until fragrant.

Add the diced green pepper and stir-fry for another 2-3 minutes until slightly softened.

Return the cooked chicken to the pan. Add the roasted peanuts and spring onions.

Pour the sauce mixture over the chicken and vegetables. Stir well to coat everything evenly.

Cook for another 2-3 minutes until the sauce has thickened and everything is heated through.

Season with salt to taste.

Serve hot with steamed rice.