Kabab Koobideh

Grate the onion and squeeze the juice out through a cloth. The pulp gives flavour; the juice would make the meat too wet to stay on the skewer.

Mix the lamb mince and beef mince with the onion pulp, the salt, freshly ground black pepper, the turmeric and the bicarbonate of soda.

Knead hard for 5 minutes, until the mixture turns pale and sticky and clings to your hand. This is what holds it on the skewer.

Chill for at least 1 hour so the fat firms.

While the meat chills, rinse the basmati rice until the water runs clear and boil it in plenty of water with the tablespoon of salt for 8 to 10 minutes, until just tender. Drain, return it to the pan, cover tightly and leave it on the lowest heat for 10 minutes to steam. Grind the saffron threads, if using, to a powder and steep them in the 2 tablespoons of hot water for 10 minutes.

Divide the meat into 8 equal portions. With wet hands, press each along a wide flat skewer, squeezing it into a long even sausage, then pinch ridges along it with your fingertips.

Put the whole tomatoes on the grill first and cook for 8 to 10 minutes, turning, until blistered and soft.

When the tomatoes are halfway done, grill the kababs alongside them over very hot coals, turning immediately and then every minute, for 5 to 6 minutes total, until cooked through with no pink left in the middle. The first quick turns set the outside so it does not drop off.

Stir the saffron water, if using, through the rice, then slide the kababs onto it with the butter, if using, the grilled tomatoes and a dusting of sumac.