Sprinkle the ground saffron on 3 cubes and ice and leave it to melt at room temperature. This will be your bloomed saffron.
In a large bowl, mix the lamb, beef and grated onion using your hands until all is very well combined. This would take about 15 minutes.
Add in the salt, pepper and bloomed saffron, then knead again for at least 10 more minutes until the mixture is sticky with a paste-like consistency and very well combined. Cover and refrigerate for one hour.
Once you're ready to grill, take the mixture out of the fridge and have a bowl of warm water close to you.
Grab a fistful of the mixture and form it into an oval shaped ball and press it onto a 1-inch wide skewer. Wet your hands again and spread the meat on the skewers using your fingers until you have a 6 inch long kebab with about ¼ to ½ inch thickness on each side.
Using your thumb and index finger, make indentations from top to bottom to ensure the meat is sticking to the skewer. Using your index and middle finger, remove a small piece of each end of the meat on the skewer to make sure it’s fully stuck to the skewer. Repeat with the remaining meat and skewers. Place all the prepared skewers on a rimmed baking sheet so the meat doesn’t touch the sheet. Thread the tomatoes on a skewer as well.
This kabob is best on charcoal grill (mangal) where the skewers are set above the burning charcoal to cook with the heat. The kabobs should not touch the grates so if you cannot remove the grill grates, place two flat-sided metal pipes or a few bricks parallel to each other either side of the grill to have the skewers elevated.
Preheat the grill. If using charcoal, make sure they're not smoking and are uniformly glowing, they should be partially covered with ashes. Your grill should be very hot for you to start grilling the kabobs.
Have a pot and a lid and some lavash at hand. Once the grill is hot, place the skewers on the grill and constantly flip to make sure the meat doesn’t fall off. It takes about 3 to 4 minutes for each koobideh to be ready. The tomato will take about 10 to 15 minutes.
Using a piece of lavash, loosen both ends of the kabab on the skewer and slide it into the pot. Cover with the lid so it doesn’t get cold while you’re grilling the rest.
Serve kabob koobideh with rice, grilled tomatoes and herbs.