Place the turkey, mayonnaise, basil, Worcestershire sauce and egg white together into a bowl.
Mix really well, then add the seasoning, and dried breadcrumbs and mix well again.
Leave to chill for 30 minutes, so the mixture can tighten, once the breadcrumbs reconstitute themselves.
Mould into 4 or 6 balls, then flatten slightly into small patties. Place a small piece of Gruyere cheese in the centre and reform into a ball and flatten again.
Heat the oil in a non-stick frying pan, than add the burgers, cook for a couple of minutes, then flip over and cook for a further 3-4 minutes.
Combine all ingredients for the relish and serve with the burgers on top of toasted slices of ciabatta and lettuce.