- 1 1/4 pounds fresh tuna steak
- A sprig of fresh basil
- A sprig of fresh mint
- 4 spring onions
- A pinch of ground coriander
- Zest and juice of 1 small lemon
- Optional: 1 fresh red chilli, finely chopped
- Olive oil
- Sea salt and freshly ground black pepper
- A handful of soft lettuce leaves, separated, washed and dried
- A handful of arugula leaves, washed and dried
- 2 tomatoes, washed and sliced
- 4 ciabatta or hamburger buns
- 1 lemon, cut into wedges
- Tomato ketchup
- Whizz the tuna, basil, mint, spring onions, coriander and lemon zest and red chilli, if using, together in a food processor or, alternatively, chop them all up together finely with a big chopping knife. Tip the mixture out on to a clean work surface and divide into four equal pieces.
- Wet your hands (so the tuna won't stick to them) and shape the lumps of tuna – first into balls, then into burgers by patting them down with the palm of your hand. Chill the burgers for at least half an hour to let them set.
- Heat a barbecue or griddle pan until hot. Brush the burgers on each side with a little oil and season with a little salt and pepper. Grill for 2 minutes on each side or until cooked through – the cooking will depend on how thick you made your burgers. It's OK to eat them when they're still a little pink inside, but if you want to cook them through then go ahead.
- Toast your buns lightly on the hot griddle pan or barbecue and make the burgers by filling each bun with a hot tuna pattie, some dressed salad leaves, some sliced tomato, a wedge of lemon on the side and some ketchup.