1 red onion, very finely sliced into rings
4 tbsp cider vinegar
pinch of sugar
4 boneless, skinless chicken thighs
4 tbsp cornflour or arrowroot
1 egg, beaten
175g/6oz gluten-free dried breadcrumbs
2 tbsp oil
25g/1oz unsalted butter
1 ripe avocado
juice 1 large lime
½ tbsp mango chutney
4 tbsp gluten-free mayonnaise
4 gluten-free burger or subway rolls, halved
chopped iceberg lettuce
Place the onion slices in a bowl. Add the vinegar, sugar and plenty of black pepper, mix well and leave for 30 mins or longer.
Place a chicken thigh on a large piece of cling film, sprinkle with water and cover with more cling film. Beat the chicken with a wooden rolling pin or meat mallet until it is thin. Repeat for the remaining 3 thighs.
Put the cornflour or arrowroot, egg and breadcrumbs onto 3 separate plates. Coat each flattened chicken thigh in a little cornflour or arrowroot, then in egg and finally in breadcrumbs; pat well. Heat the oil and butter in a large, non-stick frying pan. Fry the crumbed chicken for 10 mins, turning once, until cooked through and browned.
Meanwhile, peel, stone and chop the avocado and place in a bowl. Add the lime juice, chutney and mayonnaise, and mix well. Place the chicken in the split rolls and add a little lettuce. Top with a spoonful of avocado mixture, then with a few well-drained, pickled onion rings.