Lay the chicken breasts between two pieces of cling film and bash with a rolling pin until they are about 2cm in thickness.
Place the chicken in a bowl with the buttermilk, cover and chill in the fridge in the fridge for a minimum of 2 hours.
Mix the dry ingredients together in a bowl.
Drain the chicken and either cut into strips or leave in large pieces as preferred.
Heat the vegetable oil to 175℃ while you coat each chicken breast with the seasoned flour mixture.
Drop the first one carefully into the oil and cook separately for around 4 to 5 minutes or until golden brown and crispy (the timing will depend on the size of the chicken breasts).
Drain on kitchen paper and repeat with the other chicken breasts.
Mix the mayonnaise and Mango Chutney together, slightly toast the rolls under a hot grill and slice the onions into rings.
Coat the base of each roll with the mango mayonnaise, top with lettuce, onion and a piece of fried chicken then finish with another spoonful of the mayo.
Add the top half of the roll and serve with homemade coleslaw and fries.