There is so much flavour held in the shells and heads of shellfish, don't throw them away instead use them to make a delicious stock.The shells, heads and legs (once meat has been extracted where possible) of lobsters, crabs, langoustines and prawns impart a lot of rich flavour – especially after they're roasted.
You don’t have to use them at one go. I have a zip loc bag in my freezer that I add prawn heads and shells into as I have them. When I have enough and have the time to make the stock, they are ready to defrost and use.
- 1kg langoustine shells, lobster shells, crab shells or prawn shells (or a mix), broken into pieces with any juices reserved
- onion, diced
- 1 small leek, finely sliced
- 1/2 fennel, finely sliced
- 1 celery stick, finely sliced
- 1 small carrot, finely sliced
- 1/2 garlic bulb, cloves smashed and skin left on
- 2 tbsp of tomato purée
- 200ml of brandy, dry sherry or white wine
- 2 bay leaves
- 1 tsp coriander seeds, lightly crushed
- 4 sprigs of fresh thyme
Rinse any shells which may be hiding grit or sand (this is particularly important with crabs) and break down larger shells into smaller pieces. This gives them a larger surface area, which touches the bottom of the pan and caramelises, creating more flavour. The easiest way of doing this is by bashing the shells with a rolling pin in a deep pan or wrapped in a clean cloth.
Heat a tablespoon of the oil and the butter in a large stock pot. Add the shells and cook over a medium heat for 10–15 minutes, stirring to avoid sticking. The shells should be in one layer on the bottom of the pan to enable proper caramelisation, so work in batches if you need to. If you are using langoustines or prawns, use a rolling pin to crush the heads open. Once nicely coloured, transfer the shells to a bowl.
Deglaze the pan to collect up all the delicious bits stuck to the bottom. Do this by turning the heat up high, then add about 50ml of the brandy. Turn the heat back down and use a spatula to scrape the pan clean. Tip these juices into the bowl of shells.
Add the remaining oil and, once hot, add the chopped vegetables and smashed garlic. Cook for about 10 minutes until caramelised, stirring to avoid any burning.
Add in the tomato puree and cook out for 2 minutes.
Add the shells back into the pot along with the delicious juices. Pour in the remaining brandy and reduce by half.
Top up with water to about 3cm above the shells. Bring to the boil and then skim off the scum which rises to the top using a ladle.
Add the coriander seeds, bay leaves, thyme and any other herbs you choose to use and simmer the stock uncovered for 2–3 hours. Make sure the stock stays at a gentle simmer rather than a rolling boil, and periodically skim off impurities floating on the surface.
Once ready, place a colander over a large bowl and line with muslin or a thin, clean tea towel. Carefully pour the pan's contents into the colander. Use the back of a ladle to crush the shells, making sure you extract every last bit of stock.
You can now either return the stock to the pan and reduce further, or chill. The stock will keep for 2–3 days in the fridge or freeze for up to 3 months.