Preheat the air fryer to 200C (see Don't have an air fryer?). Thinly slice the spring onion. Crush or finely chop 2 garlic cloves. Cut the chicken into 2cm chunks. Combine ½ tsp cornflour and 60ml (¼ cup) water in a bowl. Stir in the garlic, hoisin sauce, 1 tbs soy sauce and 2 tsp white vinegar and season with pepper.
Step 2 — Air-fry chicken
Put the chicken, Chinese barbecue seasoning and remaining cornflour in a bowl. Season with salt and pepper and toss to coat. Generously spray both sides of the chicken with vegetable oil and put in the air-fryer basket, in batches if necessary. Air-fry the chicken, turning halfway, for 6-8 mins until golden and cooked through.
Step 3 — Cook noodles
Meanwhile, bring a medium saucepan of water to the boil. Thickly slice the pak choy stems, keeping the leaves whole. Cook the noodles in the pan of boiling water for 6 mins. Add the pak choy stems and cook for a further 2 mins or until the noodles and pak choy are just tender. Drain, then rinse under cold water to prevent the noodles from sticking. Return to the pan.
Step 4 — Add sauce
Add the pak choy leaves and hoisin mixture to the noodles and pak choy stems. Cook over medium heat, tossing, for 1-2 mins until the sauce clings to the noodles. Remove from the heat. Taste, then season with salt and pepper.
Step 5 — Serve up
Divide the noodles and pak choy and crispy chicken among bowls. Scatter over the spring onion and enjoy!
Step 6 — Don't have an air fryer?
No worries, you can cook the chicken in a frypan. Heat 2 tbs vegetable oil in a medium frypan over medium-high heat. Cook the chicken, stirring, for 3-5 mins until golden and cooked through.