Paul had been requesting French onion soup for, I don't know, about 2 years? And I kept putting it off, partly because I knew there were so many different ways to make it and I had no idea which to try first. But Paul was pretty adament about trying Thomas Keller's version in the Bouchon cookbook. Two things about this recipe stood out at once: there's no alcohol involved in the cooking--no wine, brandy, or sherry, which nearly every recipe for French onion soup calls for (he does call for sherry vinegar at the end, but that's different). And the onions for the soup cook for 5 HOURS. Much, much longer than your typical formula for caramelized onions. But these are not your typical caramelized onions. Oh, no. These are onion butter.
All it takes it about 8 large onions, a stick of butter, a little salt, 5 hours, and a heat diffuser, aka simmer mat or flame tamer. Above is the one I got off amazon.com for about 10 bucks. The heat diffuser is a little disk that you place directly on your burner (gas, electric, ceramic, whatever) in order to evenly distribute the heat, so you don't get "hot spots" in the pot which lead to burned food. Only with a heat diffuser, and a very sturdy pot, can these onions even withstand the torture of 5 slow, hot hours. Being in the pot without a heat diffuser would be like going on a five-hour bike ride in Joshua Tree National Park and putting sunscreen on only half of yourself. Hot spots.
Start out by slicing about 8 large onions, or 7 quarts' worth. Throw them in a big heavy pot (this is our 8-quart Le Creuset) set on top of the heat diffuser and turn the heat to low. Toss in a stick of butter and a tablespoon of kosher salt.The onions will give off a lot of liquid and start cooking down quickly. You'll need to stir them about every 30 minutes or so. This is after about 1.5 hours... and this is after hour 4. If by the fifth hour they aren't dark brown and wine-scented, turn the heat up a bit and stir them more frequently. They'll color up and become the richest little devils you've ever tasted. Like so. The amazing thing is that what started as 7 quarts of onions is now a mere 2 cups, but the same amount of butter is still in the pot. It's gotten acquainted with the onions and melded together so what you have now isn't really onions. It's like flavor magic. Truly, these do taste like they were cooked with a bottle of red wine. At this point, do whatever the heck you want with them. I'm no one to boss you around. But here are a few suggestions: Use them on a pizza. We made this one with 5-hour onions, smeared around sort of like a pasty sauce, sauteed squash, prosciutto, and smoked gouda. Oh. My. Goodness. Or, use them on a sandwich--they spread like jam once heated up a little bit (if you take them cold from the fridge, they're stiff because of all that butter). This was the beginning of a beautiful sandwich: 5-hour onions, roasted pork tenderloin, vinegary greens. Very good stuff. Or, stick with a more classical use, and make good 'ol onion soup. Thomas Keller's recipe really is pretty simple: Place 1.5 cups of the cooked onions in a pot and sift a tablespoon of flour over them, cooking on low heat for a couple of minutes. Pour in 3 1/2 quarts of very rich beef stock. Add a sachet of 2 bay leaves, 12 peppercorns, and 6 thyme sprigs, tied together inside cheesecloth. Simmer for about an hour or so, until reduced to about 2 1/2 quarts. Season with salt, pepper, and a few drops of sherry vinegar. (The complete recipe, including croutons, can be found here.) You will be very pleased with yourself.
5-hour onions (adapted from Bouchon)
- 7 quarts peeled, sliced onions (about 8 large yellow or white)
- 1 stick unsalted butter (8 tablespoons)
- 1 tablespoon kosher salt
- Place a heat diffuser over a burner, and a large heavy pot (8 quarts at least) on the diffuser. Melt the butter over low heat.
- Add the onions and salt, and cook over low heat for 5 hours, stirring every 30 minutes or so.
- Use as your heart desires.
makes about 2 cups.