Season the pieces of chicken and stiffen them in butter; add 100 g (3½ oz) sliced onions previously cooked in butter and cook together without colour.
Remove the pieces of chicken, arrange in a deep dish and keep warm.
Add ¼ dl (1 fl oz or ⅛ U.S. cup) brandy to the pan and reduce; add 1 dl (3½ fl oz or ½ U.S. cup) each of cream and Velouté then pass all through a sieve.
Reduce this sauce until fairly thick and finish away from the heat with 50 g (2 oz) butter, the juice of ½ lemon and 1 tbs of Madeira. Pour over the chicken and garnish with 10 slices of truffle.