Many people have actually properly researched this and I find it fascinating, the things that cookbooks can tell us about how we used to live, what used to be important. My mum's OLD cookbook has recipes for tanning hides and making soap, as well as instructions on how to set the table for a formal dinner with seven courses...

When I left home, Mum gave me this cookbook: the Readers Digest Cookery year. It follows through the year with meals using seasonal produce (Northern Hemisphere) and each month also has a special topical section - marmalades, wedding banquets etc. And then at the back there's an extensive section on the cooking basics - how to make roux and choux pastry and every other kind of pastry, how to make jams and jellies, how to make sabayon, how to make bread... You can see how abused this book has been over the past 4 decades... but now the recipes seem quite dated, a bit quaint or just plain weird. 

The section at the back is probably the most useful still but there are a few outstanding recipes still in use and the poulette sauce is one of them. It's great to go with broccoli, light and lemony. Best ever application was with florets of homegrown broccoli and fresh homemade pasta.

So here is how to make Poulette Sauce, courtesy of the RD Cookery Year - 

POULETTE SAUCE

Cook some broccoli in lightly salted water until tender, then lift out the broccoli and keep it warm.

Melt 25 - 50gm of butter in a small pot and take it off the heat. Stir through a  dessertspoon of plain flour, and return to the heat, stirring until the flour colours up a bit. Add 1 cup of the cooking liquid from the broccoli, bring this to the boil over a gentle heat and simmer for about 5 minutes. In a cup, beat an egg yolk with the juice of half a lemon with 2 Tablespoons of the hot sauce. Take the sauce off the heat and stir the egg mixture through gently. Add 2 Tablespoons of cream (optional I reckon). Keep the sauce warm but don't return to the heat or it'll curdle. Check seasoning and adjust with S & P, and more lemon juice if needed. 

Plate the broccoli and serve with the sauce. 

Simple and effective .... old but good.