Caramelizing onions

[alexia]

Has anyone ever caramelized onions in the oven? I'm doing about 4-5 lbs of them at once in the usual way on the top of the stove. But it occurs to me that it might be possible to just pop them in the oven at a nice steady temperature of, say 300 or so and "forget em" instead of standing over them turning to get the ones on top caramelized and keep the ones on the bottom from burning.

[chiffonade]

I see no reason you can't do this in the oven. 300 might be high though...anyone got any thoughts on the temp? When I do baked beans I leave them in the oven overnight at around 225, no higher than that. The occasional "stir" wouldn't hurt either, just to make sure everything's OK and to ensure even cooking.

[Suzanne]

Chiff is right -- try a lower temperature, and stir them from time to time. And of course keep them covered, so they won't dry out.

Some months ago I saw instructions for doing them in a crockpot: fill it with sliced onions, add a stick of butter, cover it, turn it on, and either 12 or 24 hours later, take out caramelized onions! Haven't tried it, since I don't have a crockpot. But if I ever got one, I'd certainly try this.

[Anneke]

Suzanne, if you keep it covered, won't it just sweat instead of caramelizing? The juices will have no where to go and I 'm not sure I see how the onions could brown. Just hypothesizing; I've never tried it in the oven...

[Plum]

That makes sense Anneke, it explains why my 'caramelised' onions just go soft (if I'm lucky) and stay pale. What's the usual way you're supposed to caramelise onions? Do you have to add sugar? The way I've been trying (butter/olive oil, saucepan, long slow heat, covered) just isn't working.

[alexia]

To do a modest amount of caramelized onions that can be done in a single pan, I prefer doing them in an enameled pan as it gives a better modulation of the heat. I start them off with a lid to soften them up, then remove it so that they will caramelize. When doing larger amounts I have to go to other larger pans and find my old thick restaurant grade aluminum pans work much better than ss (including All Clad & Cuisinart, which both tend to burn if not watched continuously). (What I hoped in my original query was to draw on the experience of others who may have used the oven to find out if it can be done in large quantity without standing over it. I find it hard to believe that restaurants do it the same laborious ways I have been doing.)

Seasoning will vary according to my intended use. If I use them for a pissaladiere, I add only a pinch of salt as I want the contrast between the sweetness of the onions and the saltiness of the anchovies and olives. For other uses I might salt them more. I find most onions are sweet enough without adding sugar, but tasting them along the way will determine that. I usually use either Spanish, Red, or sometimes Vidalia. In fact, my more usual addition is a touch of either Spanish, Banyuls, or Rice (I've seen recipes calling for Balsamic, but I prefer these) vinegar or some Port or other wines to make the flavor a little more complex. Sometimes I will use a little thyme or other herbal flavors either during cooking or when I assemble the dish. Obviously, seasonings are totally flexible depending on final use.

[Plum]

Thanks alexia.

Does it matter what the depth of the onions is? Maybe i have them too deep and they're just steaming themselves.

Plum

[Anneke]

For large quantities you could probably use a large rondeau or tilt pan. I don't usually cover them at any point in the cooking process. A small amount of salt is all it needs to get them sweating out their liquid; I keep it uncovered to get that evaporated as quickly as possible. A bit of sugar helps it to caramelize (got that from Julia Child). At home I always do it in a heavy bottom ss pan. Never had a problem. I like to finish mine with Port and a touch of balsamic.

Sorry Alexia, I've never seen anybody trying it in the oven. I think it would dry them out though and cook it rather uneavenly.

[chiffonade]

We used to do a great confit of onions using a bit of balsamic vinegar. I don't imagine it would hurt the flavor any and perhaps deepen the color? How about a dash of sugar? (The addition of sugar usually adds color.)

[Suzanne]

The color comes from the cooked sugars in the onions. It's temperature over time, not presence or absence of liquid. If they reach the necessary temperature, and hold there for a long enough time, they will brown. At any rate, they do when I cook brisket. But to be sure, as Chiff suggested, a little suger and/or balsamic vinegar won't hurt, and probably WILL help. And anyway, you can always cook them covered until soft, and then uncover until they're the color and wetness you want.

[Suzanne]

Just found the post I referred to above, from someone named Chris VanderRhodes, on Chowhound:

I've only done this once but it turned out great. Slice a bunch of onions (I think 5 or 6 big onions) and toss in the crockpot with a stick of butter. Let cook on low for 24 hours or so. Voila! Caramelized onions!