French Onion Soup Is Just the Beginning

This luxurious lily soup—a roasted onion and garlic broth—is useful in countless ways

French onion soup. (Shutterstock)

French onion soup is the world’s most elegant dish. Not the kind of elegance you’d find on a white tablecloth with extra silverware, but elegant in the sense that scientists use the word. Like when a simple equation can express the relationship between matter and energy with as few ingredients as a pot of French onion soup.

Start with onion, wine, and butter, which everyone knows are some of the most flavorful examples of matter in the universe. Add energy, in the form of heat from your stovetop, plenty of time, which some people call the fourth dimension, and thyme from the garden, where that tough little herb stays green deep into winter.

Those three primary ingredients, plus herbs and salt, play off each other to become something greater than the sum of its parts. The acidity of the wine cuts through the fat, while the onion infuses that harmonious balance with pungently sweet and richly caramelized flavors. Perfection is the only plausible outcome.

Thanks to that unimpeachable equation, the hardest part of French onion soup is keeping it secret when you’re baking the onions. Because if the word gets out, those juicy, layered slabs of flavor will go missing. And how can one keep it secret when the aroma of even a pedestrian version of this delicacy can pass through walls?

Meanwhile, I have a proprietary version that includes garlic, which amps the flavor up to eleven. Both garlic and onion are members of the allium, or lily family, which helps explain why it fits in with the other ingredients of my version of this soup, which I call Rocky Mountain Lily Soup. I strain out the remains of the onions, garlic, and herbs, leaving a thin, featureless broth that I use as much as an ingredient as a dish. Sure, you can serve it with a crostini and melted cheese. It’s a fun thing to do with lily soup. But that’s just the beginning. Like any broth or stock, this liquid is useful in countless ways.

I recently cooked a piece of tough meat on the bone in a pot of lily broth. It was the perfect medium, impregnating the meat with its juicy flavor. And then again, as a chaser, using it to wash down a mouthful of food, like a sip of wine that invigorates me rather than puts me to sleep. I’ve used my lily broth to make plov, a Central Asian precursor to rice pilaf. And from time to time, I even use it to make an extra-flavorful French onion soup au gratin.

The combination of onions and garlic, both roasted until richly flavorful, amps the flavor of this broth up to 11. (Ari LeVaux)

Rocky Mountain Lily Soup

This luxurious liquid is a broth that can double easily as a soup. A stock, by contrast, has no salt or fat. Either way, it’s useful, versatile, delicious, and nutritious.

Serves 6

• 5 large yellow onions
• 5 heads garlic
• 2 sticks butter, divided
• 2 cups olive oil, divided
• 1 bottle white wine, preferably from the south of France, divided
• Thyme, preferably fresh
• 2 tablespoons beef bouillon paste, or 6 cups beef or vegetable stock
• Salt to taste
• For au gratin: crusty slices of white bread and grated melty cheese

Preheat the oven to 300 degrees F.

Cut the onions from end to end into quarters, removing the dry skins. Separate the garlic heads into cloves. Cut off the scabs at the bottoms but leave the skins on, so they hold the cloves together down the road.

Put the trimmed garlic cloves into a small baking dish, along with 1/2 stick butter, 1 cup olive oil, 1 cup wine, and a sprig of thyme. Bake for about 1 hour.

Add the onions to a large baking dish or sheet pan, with a cut side on the pan, along with the remaining 1 1/2 stick butter, 1 cup olive oil, 1 cup wine, and a few sprigs of thyme. Bake for 3 hours.

Remove the garlic cloves ahead of the onions because they can get bitter when overcooked. They should still be bright white when you take them out. Onions can also overcook to a bitter place, but it takes a lot longer, and might be impossible if they are immersed in butter and wine, all of which will be completely absorbed by the onion eventually.

When the onions are done baking, they will have brand new dried peels and insides full of luscious juices. And like those onions, those roasted garlic cloves are also a flight risk, especially when your family figures out they can smear them on toast.

When all of the alliums have thus been cooked to absolute perfection, prepare a pot of beef or veggie stock (or broth, or bouillon—the only meaningful difference being how much salt and oil they contain. That’s why we haven’t added any thus far; we’ll add it before serving as needed).

Add the baked onions and garlic, along with all of their juices, and the rest of the wine, to the pot of stock. I use a pasta basket insert for this, which allows me to easily pull out and remove the solid parts of the broth, including all of the garlic and onions, instantly leaving behind a thin, versatile broth. Add salt to taste.

If you want to serve it the way normal people serve French onion soup, with bread and melted cheese, then ladle up a serving of soup into a bakeable bowl, and turn the oven to broil. Smear a clove or two of garlic onto a slice of bread and place it atop the soup. Sprinkle the bread and soup with a quarter cup of grated cheese per bowl, and broil for about 7 minutes, or until the cheese has fully melted and started to brown, with the bread that isn’t covered by cheese starting to toast. Set aside to cool, so nobody burns their mouths, which they would do, because they would be insatiable with that aroma in their faces. When it’s cool enough that your guests can dive in with abandon, serve it.