1. In a pan, melt 40g of the butter over a low heat.
2 .Add shallots and mushrooms and sweat for 1 minute.
3. Increase heat, pour over brandy, ignite with a match and burn off alcohol.
4. Add wine and reduce by half.
5. Pour water over Major Lobster Stock Base and mix well. Add stock to pan.
6. Add Bouquet Garni, tomatoes or tomato puree and cayenne pepper. Simmer for 15 minutes.
7. Stir in cream and bubble the sauce for a further 15 minutes. Remove Bouquet Garni.
8. Transfer to a food processor and whizz for a further 2 minutes.
9. Strain through a fine mesh conical sieve into a clean saucepan.
10. Bring back to the boil and stir in the cornflour. Season with pepper.
11. Off the heat, whisk in the remaining butter a little at a time.