Oh, French onion soup. I’ve been a vegetarian since I was a kid, and I remember being devastated when I realized that French onion soup had beef broth in it. It’s kind of obvious, right? I mean, something in there is giving it all that beautiful umami, and so many soups are made with meat broth anyway, especially in restaurants. But to a kid, if something isn’t obviously a hunk of meat, it’s vegetarian, right?
So I set out to make a brown broth. But despite this being for French onion soup, the broth turned out very… Japanese. I was inspired by classic vegetarian dashi, along with a few little tweaks to get a really deep, beefy flavor.
While the broth adds some good flavor, let’s be clear here — this is an onion soup. Most of the flavor is coming from those lovely little caramelized onions. This may be a cheap meal but it’s not exactly quick. Rushing the onions will not serve you in your quest for deliciousness. If you want to enjoy this as a weeknight dinner, the way to accomplish that is to caramelize the onions and make the broth ahead of time and refrigerate or freeze until needed.
So with that said: go ahead and double the butter, oil, onions, salt, and sugar in this recipe to make a double batch of onions. When they’re caramelized, remove half to store in the fridge or freezer and continue with your recipe from there. Caramelized onions require a such a slow and active cooking time, so it’s worth it to spend a little more time chopping and have something else to show for your efforts. You can plop them on almost anything (pizza! eggs! sandwiches!), make vegan French onion dip, or even save them to make this soup again, only much faster.
Serves 4 – 5
7.5 cups water
1 1/2 cups dried shiitake mushrooms
2 inch piece of dried kombu
1/2 teaspoon Marmite
1 teaspoon soy sauce
1/4 teaspoon Worcestershire sauce
1 1/2 pounds thinly sliced yellow onions (about 2 large onions)
3 tablespoons unsalted butter *
1 tablespoon olive oil
3/4 teaspoon salt
1/4 teaspoon sugar
3 tablespoons all-purpose flour
1/2 cup dry white wine
3 tablespoons cognac (optional)
1 teaspoon miso (optional)
soy sauce and freshly ground black pepper, to taste
1-2 cups grated Gruyere * **
1 tablespoon butter, melted *
12 to 16 1-inch thick rounds French bread, toasted until hard
* Vegan substitution: use all olive oil instead of a mixture of butter and olive oil to caramelize the onions. If you want to do a vegan gratinée I would recommend Earth Balance instead of the butter, and a 1:1 combination of Daiya mozzarella shreds and your favorite vegan parmesan.
** If a) you find Gruyere a little too strong, b) you like a more ooey-gooey gratinée, or c) your wallet cries at the thought of that much nice cheese: substitute up to half of the Gruyere with grated mozzarella.
Put rinsed kombu in cold water. Bring to a simmer over medium heat. Remove kombu, and add rinsed mushrooms. Lower heat to remain at a simmer, and simmer for 30 minutes. Remove mushrooms and squeeze out extra broth — reserve these for another use or discard. Dissolve in Marmite (I stick the measuring spoon in there to let the brown gold melt completely off), then stir in soy sauce and Worcestershire sauce. Set aside — you can refrigerate or freeze it for later use.
Thinly slice the onions in half moons. In a large pot, melt butter and stir in oil over low heat. Add sliced onions and toss to fully coat. Cover and leave for 15 minutes (20 minutes for double batch) to soften.
Remove lid and raise the heat slightly. Add in salt and sugar, then cook and stir onions frequently for 30 to 45 minutes (50 to 60 minutes for a double batch) — you want them to be paper lunch bag brown, and for the texture to be gelatinous, almost like preserves or marmalade. These can also be refrigerated or frozen for later use.
Once the onions are caramelized, sprinkle flour over the surface and stir over medium heat for 2-3 minutes, until the “raw flour” smell goes away. Make sure you scrape the bottom of the pot thoroughly as you stir so the flour doesn’t burn on there.
Pour in the wine and stir to combine. Then add the broth a cup or so at a time, stirring well between each addition. Taste for seasoning, then add black pepper and to taste. Hold off on adding any more soy sauce if you plan on using miso and/or topping with cheese, as both of those will bring some saltiness to the picture. Bring to a simmer, and simmer for 30 more minutes.
Remove from heat. If using miso, remove about a quarter cup of the broth, and put in a small bowl with miso. Whisk to combine, then pour back into soup. Then, stir in cognac if using. Both of these things are optional, but… they are really good. Give it a taste, and and add more soy sauce if desired.
From here, the soup can be enjoyed as is (and is vegan, if you use all olive oil to caramelize the onions). But if you’re looking to spoil yourself with that rich, restaurant-experience French onion soup, the gratinéed lid is kind of a requirement.
Preheat oven to 325 degrees. Place six oven-safe bowls on a large, foil-lined baking sheet. Bring soup back to a boil and ladle evenly into the bowls. Stir 1 tablespoon grated Gruyere into each bowl. Brush a bit of butter on each bread round then place 3-4 on the top of each bowl to cover the surface. Mound grated cheese over the bread.
Bake for 20 minutes. Preheat broiler, then brown tops under the broiler for a minute or two. (Alternatively, use a culinary torch to quickly brown the cheese when you take it out of the oven.) Carefully handling the hot bowls (use potholders!), serve immediately.