- For patties, place all ingredients in a food processor. Season, then whiz until smooth. form into patties. Dust with extra potato our and place on a plate. Chill for 30 minutes to firm up. Meanwhile, to make the slaw, combine cabbage, coriander, sweet chilli, lime juice and fish sauce in a bowl. Set aside. Heat 1 tbs oil in a large frypan with a lid over medium-high heat. Add onions and cook, turning halfway, for 6 minutes or until scorched and slightly tender. Remove from the pan and set aside. Add remaining 2 tbs oil to the pan. Cook patties, turning halfway, for 8 minutes. Top each patty with a slice of cheddar, then cover pan, and cook for 1 minute. To serve, spread mayonnaise evenly over bun bases, then top with a patty, onion, slaw and a bun lid. Serve.