Mix meat, onions, egg, salt and pepper well and leave in the refrigerator overnight (or for several hours).
Press the meat around long, thick metal skewers and shape evenly. (as in the image). Thread whole tomatoes on another skewer. Barbecue each side for about five minutes, turning frequently.
If skewers are not available or barbecuing is not possible, kabab-e koobideh can be shaped into long, thin portions on aluminum foil and grilled (broiled) at a high temperature in the oven. The oven should be pre-heated and the kabab-e koobideh should be placed as high as possible near the source of the heat.