How far in advance can I make a bechamel sauce before using it without having to cool, refrigerate and reheat.
For instance if I'm making a creamed spinach dish for a dinner party can I make the sauce right before my guests arrive, leave it on very low heat or in a warm oven unattended while I visit with everyone before dinner, and then assemble the final dish an hour later? How long could I push the timing? Also should I leave the sauce in a heated environment, or just on the counter and then rewarm it? Will there be a noticeable drop in quality?