I found this dish in the book The Medieval Kitchen by Redon, Sabban, and Serventi. (Here's a link to it on Amazon.com; I don't own a copy: http://www.amazon.com/The-Medieval-Kitchen-Recipes-France/dp/0226706842)
Take onions; cook them in embers, then peel them and cut them across into longish, thin slices; add a little vinegar, salt, oil, and spices, and serve.
|This is my favorite way to prepare it.|
It is well-suited for an historical cooking demonstration because you simply take the onions (sweet are best but any will do) and roast them in the fire. I have never just put them in the embers because I find it more visually interesting to put them on skewers where people can see them. Every once in a while I turn the skewer so the onion roasts evenly all the way through. The onion is done when it is very soft and is trying to slide downhill on the skewer.
Making it at home is just as simple: I put the onions in a pan (this catches the drips) and put them into the oven at about 350 degrees F for an hour or two. In other words, I slow cook them until they are very soft and squishy.
This makes the onions tender and sweet, without that classic onion bite at all.
I prefer to use just a decent balsamic vinegar and a little grating of nutmeg. It is also fine to put in some black pepper and a little salt. I only use oil (olive oil) if I feel the flavor of the onions is a little flat -- mostly I like the clear mild onion flavor without the olive-y boost. Whatever vinegar you use, make sure it is mellow enough to enjoy "as is". You don't want a harsh tang when you eat these.
|You can consider the advice on the bowl, too!|
The Verdict: Success, of course! I've used this dish many times over the last several years. The only mistakes I've made were not cooking the onions until very soft, thus leaving behind some of the harsher onion flavor (it is better to cook them "too much" rather than "too little"), and putting on too much balsamic vinegar, so that all you can really taste is the vinegar. You can drain off the excess and try to mellow it out by adding other spices and the olive oil. Perhaps you can rinse off some of the vinegar, too, although I've never tried it.
The recipe direction for "longish, thin slices" is a good one. Large or wide slices put too much onion in your mouth all at once, which I find feels like I am drowning in onion. The smaller slices are easy to eat with a fork or even medieval-style, using your fingers.