Step 1

Melt the butter in a large saucepan, add the onion, carrot, celery and thyme and fry over a medium-high heat for 3-4 minutes. Meanwhile, break or cut up the lobster shells into small pieces.

Step 2

Add the lobster shells to the pan and fry for 2 minutes. Add the tomato and tomato puree and fry for 1 minute more.

Step 3

Add the brandy and white wine and set alight with a match, to burn off the alcohol. Take care and stand back as you do so. When the flames have died down. Add the chicken stock, bring to the boil, lower the heat and leave to simmer for 20 minutes.

Step 4

Transfer the mixture to a liquidiser, in batches if necessary, and blend to a coarse puree. Strain through a muslin-lined sieve into a clean pan, squeezing out as much of the liquid as you can. The stock is now ready to use or freeze for later use.