# Clean the white kidney
beans and dried mullet at the night, and rest them in 5 cups of water for overnight. The day after, pour this mixture into a pot and boil it, until the ingredients soften.
# Put vegetable oil into a separate pot and make it hot over medium heat. Then, add diced
onions in it.
# When the
onion turns to transparent, add finely sliced
garlic cloves and grated
carrot in it, and roast the mixture for about 5 minutes.
# Add the
potato cubes on it and pre-cook it.
# Then, add boiled mixture of white kidney
bean and mullet into the mixture.
# Add black
pepper, crushed red
pepper, cumin, salt and bay leaf into the mixture and boil the mixture for about 20 minutes.
# Cast away the bay leaf in the mixture, and blend the mixture. If it is not blended well, strain it to get its smooth fluid.
# Put it into the pot again, and add 5 cups water in it. Let the mixture turn to hot over medium heat. Then, add whisked
yogurt in it and stir it constantly until the mixture reaches to the boiling temperature.
# When the mixture reaches to the boiling temperature, turn the heat to low and cook the soup for 10 more minutes.
# Serve it hot.