In 6-quart stock pot or Dutch oven, heat the butter or margarine over medium heat.
Add the onion and garlic and cook 6-8 minutes, stirring frequently, until golden and softened.
Add the curry powder and cayenne pepper and continue to cook for another minute or so.
Add the squash, carrot, and bell pepper and cook for another 2-3 minutes.
Add the broth and water. Bring to a boil. Reduce heat to medium-low; cover and simmer soup until squash is very tender, about 50 minutes.
Remove from heat and allow to cool to room temperature.
Working in batches, purée the soup until very smooth.
When ready to serve, reheat the soup, season to taste with salt and pepper, and garnish with sour cream and cilantro.
6 servings
3/4 cup