Creamy Turkey Soup

1 small onion, diced
2 tablespoons margarine
2 cups water
3 chicken bouillon cubes
2 cups diced turkey, cooked
1/2 cup chopped celery
1-1/2 cups diced potatoes
1 cup diced carrots
2-1/2 cups milk
2 tablespoons flour
1 teaspoon salt
1/2 teaspoon pepper

Sauté onion in margarine until translucent. Add water, bouillon cubes, turkey and vegetables. Cover and simmer gently until vegetables are tender.
     Add a small amount of milk to the flour, stirring until mixture is smooth. Add remaining milk, salt and pepper. Stir milk mixture into soup. Simmer, stirring occasionally, until soup thickens slightly. Remove from heat and serve.