Making a bisque isn't all that difficult, Eastshores and it is absolutely delicious when used as a sauce for your seafood ravioli.
You can start with fresh lobster or even use frozen ones, as long as the heads are still on. The heads are where the flavor is, not so much in the shells. Boil the whole lobsters as usual, remove the meat.
Over to the bisque; use a wide pot, add olive oil, add the heads and shells on medium high fire. Stir frequently and break the shells/heads in smaller pieces-while frying- with the end of a rolling pin or anything else that will help. Let the shells fry for quite a while. Add a small tbsp of tomato paste to the shells and -very important; let the tomato paste fry sufficiently to remove the bitter taste from it; keep stirring it with the shells. After that, add a tbsp of pastis or ouzo or raki. Let the alcohol evaporate completely. Add a small tbsp of flour and stir in; the whole thing will look messy, don't worry.
Add around 1/2 cup of dry white wine or vermouth and let the alcohol evaporate for a little while. Now add chickenstock or fishstock or plain water. I mostly use water or chickenstock and I avoid fish stock as it can smell and taste very badly when cooked too long. Now add aromats like a little celery, onion, clove of garlic, tarragon, bouquet garni etc. Let simmer for around 30 minutes. Strain but push all liquid out of the remaining solids while they are in your sieve.
Reduce the liquid, add a little cream, taste, add s&p and a pinch of cayenne powder.