Some sort of seafood stock is the key here, and you’ve got options: For shrimp stock, simmer shrimp shells (from about 1 or 2 pounds of shrimp) in 5 cups of water for 15 minutes. Done. You can do the same with lobster shells and legs, either raw or cooked (I use all the scraps from lobsters that I’ve cooked and devoured). For fish stock, combine 1 pound…