Curry carrot soup

Place carrots and water in a 1-quart saucepan and bring to a boil over medium heat. Boil for 20 minutes. Carrots should be very soft. Drain carrots, place in a food processor, and process until carrots are pureed. In a 1-quart saucepan, melt margarine over medium heat, then sprinkle in flour. Stir rapidly with a small whisk to make a paste, then slowly add chicken broth, stirring continuously. Once all the broth has been poured in and the mixture is smooth, add pureed carrots and yogurt, stirring well. Add seasonings and continue to mix with whisk. Bring to a boil, then reduce heat to low and cook 5 more minutes, stirring frequently.