Clean the carrots and cut them into cubes. In a small pot heat the butter and sauté the carrots for 1-2 minutes. Then sprinkle with the black sugar and continue for 1 minute. Add spices, broth and salt according to your preference. Let the carrots boil for about 10 minutes.
Swab the mixture in the blender and return it to the pot. Check the soup and, if necessary, dilute with additional hot broth or water. Add sauce and simmer for 5 more minutes.
Serve with strained yogurt, rose water, cumin and fresh coriander.