Harissa Lamb Burgers with Feta

Cut a few slices of onion and reserve for serving, then finely chop the rest. Tip the lamb into a bowl and add the chopped onion, harissa, Feta, 2 tablespoons mint, a little salt (as the Feta is quite salty) and plenty of black pepper. Mix together well. Divide in half and roll each portion into a ball, then flatten into a burger shape.

Heat a lightly oiled griddle pan or frying pan and cook the burgers for 5–7 minutes on each side until cooked through.
Meanwhile, make tzatziki in a small bowl: mix the cucumber with the Greek yogurt and remaining mint and a little salt and pepper.

To serve, place some lettuce on the bottom half of each bap, top with a little torn mint, the burger, then some tzatziki and the reserved sliced onion and the top of the bap.