Leave it to the French to take a mountain of sliced onions, a bit of broth and a few Provencal herbs and transform them into a heavenly, melt-in-your-mouth soup. The dismal weather that has become something of a default around here this winter has had me in the soup mood, and this one is astonishingly simple—from ingredients to technique.
One thing that sets French onion soup apart from others is the amount of time spent simply preparing the onions. You can use a mandolin or processor to make quick work of slicing them, but there isn’t much you can do to speed up the cooking. In a Dutch oven on the stovetop, it can take up to two hours to properly caramelize the onions—that is, to draw out their moisture and let all the natural sugars burst forth. If you work too quickly, you’ll have sautéed onions, but they won’t have the luxurious sweetness that is a signature of French onion soup. One way to get this done with minimal fussing is to use a slow cooker, set on the lowest setting. Another is to caramelize them in the oven, allowing a low-and-slow transformation, perhaps even overnight. The extra effort and preparation time has landed this soup in the Sunday Supper category here on Comfort du Jour, but I promise—however you approach the whole onion caramelization thing, it is well worth the wait.
If you’re the make-it-all-yourself type, feel free to slow roast some beef soup bones and make your own stock, too. I had a momentary lapse of reason and tried this myself, but mainly ended up with a bucket full of tallow and two sinks completely filled with dirty pots and bowls. As far as I can tell, a good quality store-bought stock is a gift from heaven, so that’s what I used. Make it vegetarian with a good vegetable stock or combine the two as I did for wonderful layers of flavor.
The final touches on top of French onion soup are toasted baguette or bread slices and melty shredded Gruyere cheese. Yes, it’s a luscious bowl of classic French comfort food that is guaranteed to warm you up in these final weeks of winter.
4 pounds sweet onions, sliced
1 stick unsalted butter
Kosher salt and freshly ground black pepper
1 1/2 teaspoons Herbes de Provence seasoning* (see notes)
1 bulb roasted garlic
1/2 cup dry wine (red or white, for deglazing the pot)
8 cups (2 quarts) low-sodium broth or stock (beef, vegetable or combo)
Crusty French bread slices (toasted, for serving)
Shredded Gruyere or Swiss cheese (about 2 Tbsp. per serving)
Herbes de Provence is a blend of seasonings native to the Provencal region of France, and the brand I use includes thyme, rosemary, garlic, lemon peel and lavender. The combination of this seasoning is aromatic and typically used somewhat sparingly, but it is such a central flavor to French onion soup, I’ve used a good amount in this large batch. As always, take note of the salt content of any seasoning blend you use so that you can adjust the overall salt accordingly.
I’ll walk you through it, and you’ll find written instructions below, plus a link to download the recipe for your files. 🙂
- Slice onions about 1/4” thick, preferably from stem to root ends, rather than into rings. For this recipe, I think it’s helpful to have the onion pieces generally the same size, and the top-to-bottom slicing will help you achieve that.
- Place a heavy Dutch oven over low heat, and melt the stick of butter in it. Add the onions at the same time as the butter if you’d like. But if you are using a slow cooker, melt the butter first, then toss the onions thoroughly to coat before cooking on low setting. Season with salt and pepper. Stir the onions around in the pot, and resist the urge to turn up the heat. Proper caramelization is important for this recipe, and it’s a long, slow process. Happily, you don’t have to stand over it constantly; as long as you stir the onions occasionally, it’s fine.
- After an hour or so, start watching for signs of browning on the bottom of the pot. This is a sign that the onions are caramelizing and once it begins, it proceeds more quickly. Stir more frequently from this point, but do not increase the heat.
- When caramelization is complete, the onion mixture will begin to look like it’s frying rather than simmering—this is because the moisture content has fully dissipated. Add the herbs de Provence, roasted garlic, salt and pepper.
- Pour the wine into the pot, and use your utensil to scrape up any browned bits that have stuck to the pot. The acidity of the wine will dissolve those tasty bits back into the onion mixture.
- Add the stock, bring to low boil and then reduce to simmer, covered, for a couple of hours.
- Serve the soup in warm bowls or crocks, place the toasted bread on top, then scatter shredded Gruyere or Swiss over the bread. If your bowls are broiler-safe, put them on a baking sheet and broil just long enough to make the cheese gooey. Alternatively, you could put the bowls in the microwave for about 30 seconds, or go high-tech with a kitchen torch and brûlée the cheese into blissful melty goodness.