Cut the unpeeled eggplant into 1/2-inch slices and sprinkle liberally with salt. Leave for 30 minutes then pat dry with paper towels. This process allows the salt to draw out some moisture from the eggplant.
Heat oil in a deep frying pan and then fry eggplant until lightly golden on both sides (they do not need to be cooked through—you are just adding color and a bit of flavor). You will need to do this in batches and add more oil as needed. Remove the cooked eggplant slices to a plate covered.
Oil will leach from the cooked eggplant slices, so return this to the pan to reheat and then add the onion. Fry until soft.
Add 3 of the crushed garlic cloves, tomato slices and red chile flakes and cook until the tomatoes break down and a sauce is formed. Add a little stock and seasoning as needed. Remove from pan.
Place a layer of eggplant slices back into the pan. Top with sauce. Repeat until all the eggplant slices are back in the pan. Pour in any remaining oil from the eggplant and onion and add the remaining stock. Cover and simmer gently for 10-15 minutes until the eggplant is tender.
Combine the yogurt, salt and remaining garlic clove. Mix well then spread over the base of the serving dish.
Add the eggplant slices, lifting eggplant carefully to keep intact. Top with remaining sauce and onions. Sprinkle with some fresh mint and coriander for color.
Note: The traditional recipe calls for chakah, which is plain yogurt that has been drained overnight. This makes it a little thicker and drier.
