Bisque is a creamy and smooth French-style soup and usually made with crustaceans like prawns and crabs. The shells are very important in the making of this type of soup. The trick is to sauté the prawn shells and heads slowly, for at least 15 minutes. Instead of using rice as a thickener, you can also use flour to make a roux to thicken the bisque. It is best to serve this soup with toasted bread or garlic bread.