This recipe comes from Mastering the Art of French Cooking, 1961. 'If the natural moisture content is now withdrawn beforehand, cucumbers exude so much water as they are heated that you usually end up with a tasteless mush and swear never to cook cucumbers again. Blanching for 5 minutes before cooking will remove unwanted water, but also most of the cucumber flavor. A preliminary sojourn in salt draws out the water and also the bitterness, if they are the bitter European type, yet leaves…