Divide the mince into 4 equal portions and shape each into a patty sized to fit the burger buns. Season with salt and freshly ground pepper.
Mix the plain flour with the spices, season with salt and freshly ground pepper and tip it into a shallow bowl. Put the blitzed cornflakes in a second bowl and the beaten egg in a third.
Coat the chicken patties in the seasoned flour, then thoroughly in the beaten egg and finally in the cornflakes.
Heat a generous glug of neutral-tasting oil in a frying pan and fry the chicken patties until golden and crisp on both sides and cooked through.You can also cook them in an air fryer at 190°C for about 18 minutes, or in a fan oven at 200°C for 18-22 minutes, depending on the thickness of the patties. Spray them lightly with cooking spray before they go into the air fryer or oven.
Meanwhile, stir the mayonnaise together with the Dijon mustard, and warm the burger buns in the frying pan, the oven, a toaster or the air fryer.
Spread the top and bottom halves of the buns with the mayonnaise. Lay the cheese on the bottom halves and set the hot chicken patties on top so the cheese melts. Add the lettuce, finish with the top halves and serve straight away.