Crush the lobster shells and lobster sections, fry them gently in butter. Add the matignon and sauté. Add the tomato puree and sauté. Flambé with cognac, extinguish with white wine and reduce. Add fish fumet and kitchen herbs, boil down for half an hour.
Press through a pointed sieve, then strain through a straining cloth and set aside to cool.
Skim off the butter floating on top and clarify.
The remaining stock can be used to make a crustacean fumet or possibly a bisque.
Our tip: If you like to cook with fresh herbs, it is best to get kitchen herbs in pots – so you always have everything ready!