French onion soup isn’t difficult to make, but it does take some time. You’re looking at 45 minutes to caramelize the onions and another 90 minutes to simmer the best flavor. But when you pull the serving bowls from the broiler and see the bubbling cheese on top, you’ll realize it’s a worthwhile project.
Take your time on the onions, you want them a dark walnut color. And we must talk broth/stock. Taste first if you’re going to use store-bought; many taste terrible, and you don’t want to ruin all your hard work. Check the freezer at your grocer for high quality options. For shelf-stable brands in the 32 oz. boxes, I prefer Imagine to Pacific, Swanson is always good for chicken broth, and if there’s a low-sodium option, go for that. Sometimes I do use a concentrate (Better Than Bouillon), but you have to watch the salt level of the soup. Sometimes I use the concentrate to make only part of the 10 cups stock, making up the remainder with water or another option. Lots of options.
My recipe is adapted from Julia Child’s French Onion Soup in her book, The Way To Cook. Plenty of butter and good amounts of vermouth and Cognac. (I love that woman!)
Amy’s Kitchen Coach Tips:
- For easy to eat onion pieces, slice onions in the pole-to-pole direction rather than across the equator
- Don’t add extra salt if you’re using concentrated stocks or broths, as they are often very salty. If you’re using homemade stock or broth, add 1/2 teaspoon of salt with the sugar.
- To toast the bread, slice a baguette on the diagonal about 1/2-inch thick, lightly butter one side and set on a rimmed sheet pan. Bake 375 for 5 – 10 minutes until crisp. To make things even easier, put the cheese on top of the baguette slices (and bake) instead of gratinée-ing the bowl. Put the cheese toasts in the bottom of each bowl, then ladle in the hot soup.
French Onion Soup Gratinée
- 4 or 5 large yellow onions (about 2 1/2 lb. total), peeled, halved, then sliced no thinner than 1/8"
- 3 tbsp unsalted butter
- 1 tbsp olive oil, avocado oil, or other cooking oil
- 1/2 tsp granulated sugar
- 2 tbsp all-purpose flour
- 10 cups beef broth or stock (homemade or made with condensed bouillon; 2 tablespoons Better than Bouillon in 10 cups water), at least 2 cups of which should be hot
- 1 cup dry white French vermouth
For serving: Cognac (a teaspoon or two for each bowl), buttered and toasted baguette slices (or other crusty bread, like a levain), grated Swiss cheese (Gruyère is nice)
Melt the butter and oil in a large dutch oven or stockpot set over medium heat. Add the sliced onions, stir them around with a wooden spoon, cover the pan, and cook slowly until tender, about 10 minutes.
Remove the lid from the onion pot, increate heat to medium-high, sprinkle in the sugar, and cook the onions until medium brown in color and caramelized, stirring frequently, about 45 minutes.
Sprinkle the flour over the onions and stir for 3 or 4 minutes. Remove pot from heat and stir in 2 cups of hot stock. Return pot to heat and bring to boil. Add remaining stock and vermouth. Cover loosely and simmer very slowly for 90 minutes, adding a little water if the liquid reduces too much.
To gratinée serving bowls: Preheat oven to broiling; position rack about 6 inches from heat. Pour a teaspoon or two of Cognac into each serving bowl. Ladle in the soup, about 2/3 full, and set on a rimmed sheet pan. Float a slice of toasted bread in each bowl (perhaps 2 baguette slices will fit) and sprinkle with grated cheese. Broil a few minutes until cheese is bubbly and starting to brown. (Alternatively, bake in 375° oven until cheese is melted, remove from oven, and brown the cheese using a hand-held butane torch.)