Supremely Supreme Chicken Supreme

According to Larousse Gastronomique (1938) a traditional, classic "Sauce Supreme" is based on a Veloute Sauce which has been reduced, and has added cream or Creme Fraiche. For a Chicken Supreme the Veloute sauce is made with a chicken stock to which it is usual to add the flavour and texture of some lightly sauteed mushrooms and a drop of lemon juice. I'm going to follow Mrs Beeton's ideas about all this almost to the letter except that she uses an egg yolk as a thickener, reference to which I can't find anywhere else so I'm going to leave that out, and I'll use Lime instead of Lemon because I just happen to have one half-used already and simply don't want to waste it.

Chicken Supreme
INGREDIENTS
2oz unsalted butter
6 button mushroom caps
12 black peppercorns
Some Parsley stalks
2oz flour
1pt chicken stock
Salt & Pepper
Lemon Juice
Some double cream
1oz butter (additional)
Nutmeg to taste
Lemon Juice (additional)

1 whole, cooked, chicken breast

METHOD
Melt the butter in a saucepan, add the Mushrooms, Peppercorns and Parsley and gently fry for 10 minutes then add the flour and cook for a couple of minutes more then slowly incorporate the stock and finally cover and cook for an hour at a SLOW simmer.
NOTE. Keep a watchful eye, don't let anything, at any stage, brown or catch. Another name for this concoction is "French Fawn Sauce": there is nothing brown about it!! So it may be best to complete the cooking in a double boiler if you can (I've improvised, my saucepan set just happens to stack in a way that I can build a double boiler. The photo shows the idea.)
At the end of the cooking time pass the sauce through a sieve and recover the mushroom. Add some lemon juice to the strained sauce plus the rinsed recovered mushroom and reheat gently. When almost at a boil add the cream and stir through to complete. Check seasoning, adding ground white pepper if necessary (keeps the colour theme going!) And there we have it: a Chicken Veloute. Next stage...turn it into a Chicken Supreme (I told you it was complex!) But that is going to have to wait - it's siesta time and I feel some Roy Orbison and a glass of Irn-Bru WKD coming on.

OK, on I go....bring the veloute slowly up to boiling point adding some nutmeg to taste, some more cream with a knob of butter and a little more lemon juice as it warms. Place your whole chicken breast in the sauce to heat through and also (optionally) add a few whole mushroom caps to cook through for use as a garnish, stirring ever so gently to prevent sticking until the mushrooms are "Al Dente" at least. Job done. Serve the Chicken Breast over boiled rice and dress copiously with the sauce and garnish with the Mushrooms. For myself I also included a few pan-fried Asparagus tips on the side.

FOOTNOTE
I opted to leave an egg yolk out of the sauce but didn't compensate for that omission. Too late now but next time I'll cut back the stock to 900mls or so, or put a beaten egg yolk after the nutmeg, extra cream etc (and when the mushrooms are nearly "done".) But then the sauce won't keep, it has to be used immediately the yolk has thickened it but not set it, and I hope that you can understand what I'm trying to say.