Combine chicken mince, egg, breadcrumbs, McCormick Oregano Leaves, Chilli Flakes, salt & pepper. Form into 8 patties.
Heat 1 tbsp oil in a large frypan or BBQ plate over high heat and cook patties, turning occasionally for 4 minutes each side.
Heat 1 tbsp oil in small frypan or BBQ plate and cook onion until caramelised.
Serve patties in warmed buns with cheese, onions, lettuce and tomato.