Heat the oil in a pan and fry the onion and garlic, over a low heat, for 4-5 minutes. Add the mushrooms and cook for 3 minutes. Allow to cool and transfer the mixture to a mixing bowl. Add the mince, cumin, coriander, egg and breadcrumbs and mix well. With floured hands, shape spoonfuls of the mixture into sausage shapes and thread onto bamboo skewers. Lightly brush the kebabs with oil and fry, grill or cook on a braai for 3-4 minutes per side, or until cooked. Serve the shish kebabs with flatbreads, tzatziki, salsa and fresh coriander.