Name: The Best French Onion Soup
Prep time: 20 min
Cook time: 30 h 30 min
Total time: 3 h 50 min
Cuisine: French
Ingredients: 3 tablespoons unsalted butter, cut into 3 pieces; 6 large onions (3 yellow onions and 3 red onions), sliced; 1 teaspoon salt, plus more to taste; 2 cups water, plus 3/4 cup for deglazing; 1 tablespoon balsamic vinegar; 1/4 cup dry red wine; 4 cups low-sodium chicken broth; 1 cup beef broth or beef stock; 1 can (about 10 oz) organic beef consommé; Worcestershire sauce, a dash or two; 6 sprigs fresh thyme; 1 bay leaf; Ground black pepper to taste; For the cheese croutons:; 1 baguette, cut into 1/2-inch slices; 4 1/2 ounces Swiss cheese, sliced thin; 1 1/2 ounces Gruyere cheese, grated (about 3/4 cup)

Classic, deeply flavored, and worth every minute of the cooking time.

January is when I finally exhale. The Christmas decorations are put away, the blogging schedule loosens its grip, and the house gets quiet again in the way I love. It is the month when I actually cook. Not holiday cooking, the kind with lists and timelines and too many dishes. Just cooking. Slow, unhurried, no reason other than I want to. And the thing I want to make on cold nights in January, almost without fail, is French onion soup.

I have been making this soup for years. It started as an adaptation of a Cook’s Illustrated recipe, and it has shifted a little each time — a splash of Worcestershire, a mix of yellow and red onions, whatever beef stock or broth I happen to have on hand. By now it is simply mine. The version I make on a cold afternoon in January, Bill somewhere nearby with a glass of red wine, the Dutch oven on the stove filling the kitchen with that deep, sweet smell of slowly caramelizing onions. It is one of those soups you do not rush. And that, in January, is exactly the point.

This is a classic French onion soup recipe — traditional French onion soup in every sense, with sweet caramelized onions, a rich beef broth base, toasted baguette slices, and a bubbling layer of Gruyere and Swiss cheese on top. It takes time and patience, but I promise you the cooking process is far simpler than it looks.

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What Makes This the Best French Onion Soup

Most French onion soup recipes taste fine. This one tastes like something you ordered in a small restaurant in Paris and have been trying to recreate ever since. The difference is patience in two places: the onions and the deglazing.

Six large onions, three yellow, three red, go into a Dutch oven with butter and a teaspoon of salt and cook covered in a 400-degree oven for nearly three hours. The yellow onions bring that familiar golden sweetness. The red onions temper it, adding a slightly deeper, more complex flavor that keeps the soup from tasting one-note. By the time they come out of the oven, they are deeply golden brown and sweet in a way that no shortcut can replicate.

Then comes the deglazing, scraping up the dark crust that forms on the bottom of the pot with small additions of water, letting it cook down, doing it again. Two or three times. Each round builds flavor you cannot get any other way. Add dry red wine and a tablespoon of balsamic vinegar, and the broth has a depth that is unmistakably the real thing. A dash of Worcestershire goes in with the broths — it is not traditional, but it rounds everything out in a way I would not give up now.

The result is a soup with layers. Rich beef broth, sweet caramelized onions, a splash of wine, a hint of balsamic, and then, at the end, oven-safe bowls set under the broiler with baguette slices and a generous covering of melty cheese. Gooey, bubbling, slightly crispy at the edges. It is the best French onion soup I have ever made, and I have made a lot of soup.

What You Need

The ingredient list for this traditional French onion soup is straightforward. A few notes before you start:

Onions: Six large onions, three yellow and three red. Yellow onions are the classic choice for French onion soup — they caramelize beautifully and have the right sweetness. The red onions bring a slightly less sweet, more savory note. Sweet onions or Vidalia onions work well too if that is what you have. White onions are not my preference here, they are sharper and do not soften as well.

Broth: I use a combination of low-sodium chicken broth and beef broth, plus one can of organic beef consommé. The consommé is the secret, it gives the broth a richness and clarity that beef broth alone does not quite achieve. Beef stock or chicken stock both work beautifully in place of the broth if that is what you have. Whatever you use, make it good quality. The broth is everything in this soup.

Wine: Dry red wine. Bill is a red wine drinker, which means there is always an open bottle on the counter in our house, which means this soup benefits accordingly. Dry white wine works too, and some classic French recipes call for dry vermouth or dry sherry. Use whatever you are comfortable cooking with.

Cheese: Swiss cheese and Gruyere, used together. The Swiss melts into a smooth, creamy layer. The Gruyere adds that nutty, slightly sharp bite and browns under the broiler into something with a little chew and a lot of flavor. You could use all Gruyere, and it would be wonderful but the combination is my preference.

Butter: Three tablespoons of unsalted butter, cut into pieces. That is it. No olive oil needed here at the start, the butter and the salt and the low, slow oven do all the work.

Dutch oven: A heavy-bottomed Dutch oven, at least seven quarts, is not optional here. The oven step requires it, and the weight of the pot helps the onions cook evenly without scorching. If you do not have one, this is a good reason to get one.

How to Make French Onion Soup

A few things to know before you start: this soup takes time. The onions alone spend nearly three hours in the oven. Plan for an afternoon project, not a weeknight dinner in a hurry. The good news is that most of that time is hands-off — the oven does the work while you do something else.

Start with your Dutch oven sprayed generously with nonstick spray. Add the butter, all six onions, and a teaspoon of salt. Cover and put the pot in a 400-degree oven for one hour. The onions will soften and release their liquid. After an hour, stir and scrape the bottom and sides, then return to the oven with the lid slightly ajar for another hour and a half to one hour and forty-five minutes, stirring once more halfway through. By the end, they should be very soft, reduced significantly, and turning a beautiful golden brown.

Now move the pot to the stovetop over medium-high heat. This is where you build the flavor that makes this soup what it is. Cook the onions, stirring frequently and scraping the bottom and sides with a wooden spoon, until any remaining liquid evaporates and the onions begin to brown — fifteen to twenty minutes. Reduce to medium heat if they are browning too quickly. Keep cooking until the bottom of the pot is coated with a dark crust, about six to eight more minutes.

Add a quarter cup of water to deglaze, scraping up all the browned bits from the bottom of the pot. Cook until the water evaporates and another dark crust forms. Repeat this deglazing process two or three more times until the onions are a deep, dark brown. This step is what separates a good French onion soup from a great one. Do not skip it and do not rush it.

Add the dry red wine and balsamic vinegar, stirring until the wine evaporates, about five minutes. Then add the chicken broth, beef broth, two cups of water, the fresh thyme sprigs and bay leaf (tied together with twine for easy removal), half a teaspoon of salt, and a dash or two of Worcestershire sauce. Scrape up any final bits from the bottom of the pot. Increase heat to high and bring to a simmer, then reduce to low, cover, and simmer for thirty minutes. Remove and discard the herbs. Season with black pepper and additional salt to taste.

While the soup simmers, arrange baguette slices in a single layer on a rimmed baking sheet and bake at 400 degrees until dry, crisp, and golden at the edges, about ten minutes. Set aside.

To serve: adjust the oven rack four to six inches from the broiler and heat the broiler. Set oven-safe bowls or crocks on a rimmed baking sheet and fill each with about one and a half cups of soup. Top with two toasted baguette slices — that cheesy toast on top is half the reason anyone loves this soup. Lay Swiss cheese slices over the bread in a single layer if possible, then sprinkle about two tablespoons of grated Gruyere cheese over each bowl. Broil until the cheese is gooey and well browned and bubbly, seven to ten minutes. Watch it — broilers vary and it can go from perfect to too dark quickly.

A Few Tips for the Best Results

Do not rush the onions. I know I have said this, but it bears repeating. The caramelization is the flavor. Three hours sounds like a long time. It is. It is also the reason this soup tastes the way it does.

Use oven-safe bowls or crocks. If you do not have traditional French onion soup crocks, any oven-safe bowl will work, just make sure it can go under the broiler. Regular soup bowls that are not broiler-safe will crack.

Toast the baguette slices before assembling. Baking them until they are dry and crisp means they hold up under the cheese and in the soup without going immediately soggy. A thick slice of a good crusty French bread also works beautifully here — the toasted bread is what stands between you and a bowl of mush, and it matters.

Add a drizzle of olive oil to the baguette slices before toasting if you like, it is not in the original recipe but it adds a little richness and helps them brown evenly.

Make the soup ahead. This is one of those soups that is genuinely better the next day. The flavors deepen overnight. Make the soup base a day ahead, store it in an airtight container in the refrigerator, and assemble the bowls when you are ready to serve. Make fresh croutons each time, they only take ten minutes and the texture is worth it.

Store leftovers with the soup and croutons separate. The soup keeps well in an airtight container in the refrigerator for three to four days. Reheat gently on the stovetop over medium-low heat, assemble fresh bowls, and run them under the broiler. It tastes just as good the second time.

A Little History

French onion soup has been around since at least the 18th century, and the story most often told traces it to the court of Louis XV, though historians are more cautious about that particular origin than food writers tend to be. What is certain is that onion soup has been a staple of French cooking for centuries, originally a peasant dish built on what was abundant: onions, water, and stale bread. The Duke of Lorraine is sometimes credited with popularizing an early version. It became the classic French bistro soup we know today in the Les Halles market district of Paris, where workers ate it in the early morning hours after the night market closed.

The version most of us make at home, the one with the deep, caramelized onions, the rich broth, and the bubbling cheese on top, is a classic French bistro soup that has crossed the Atlantic and made itself entirely at home. It is authentic French onion soup in spirit if not in origin, and I am not sure anything warms a cold January evening quite as well.

One More Thing

If you make this soup, I hope you make it on a slow afternoon when you have nowhere to be. It rewards that kind of time. Pour yourself something warm, listen to the onions cook, and let January be what it is good at, quiet and unhurried.

I would love to know: do you have a soup you make every winter without fail, the one that feels like a ritual? Tell me in the comments, I am always looking for the next thing to put on the stove.

If you enjoyed this recipe, you can find me on Pinterest for more recipes and ideas for women over 50. And if you make this French onion soup, I would genuinely love to hear how it turned out.

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