I have in my freezer shells from several pounds of shrimp which I have frozen over the past months with the idea that I might make some kind of shrimp bisque or broth with them. Any ideas? How much flavor will the shells impart & how long should I simmer them for? My thought was to simmer them in water with some onion, parsley, celery, carrot, a bay leaf, not sure about pepper corns. Then to cook shrimp, puree some of the shrimp with the broth, add cream, sherry and some cooked shrimp. So, will this work? Any other ingredient ideas? Thanks!