French onion soup, classically, relies heavily on the flavor of beef stock as a key ingredient. So some 20 years ago I decided that I would figure out a vegetarian version of this winter warmer dish that was as good, or better than, the standard meat version. According to multiple guests, I succeeded -- some even prefer this to the beef stock version because the onion flavor is clearer and sweeter.
Like other dishes where I replace a rich, meat flavor with vegetarian ingredients, the recipe relies on a lot on slow flavor layering. This means that you can't really make further major substitutions, or take shortcuts on the recipe below -- if you don't have the full two hours or some of the ingredients, just make something else. This is not part of my Good First Recipe series.
My version starts at the grocer's. You need brown onions for this (also called yellow onions), and importantly the onions you buy should have thick, brown skins unblemished by mold or dirt.
You're going to need those skins, because you're going to use them to make a brown onion stock. That's one of my tricks for replacing beef stock; the brown onion skins not only give the stock additional flavor, they also give it a rich, dark brown color, so that it looks rich as well as tasting rich. White or red onions will not work.
The other big part of this soup is low-and-slow caramelization of the onions. You need to take the full 40 to 70 minutes to carefully render the onions deep brown and sweet over a low flame. Don't rush it, and above all don't sear the onions, which will make the soup taste bitter.
You can, however, get as far as making the onion/stock soup, and then set it aside for quite a while; hours, or even overnight in the fridge. So consider making this one a day ahead.
francophilic onion soup
5-6 large brown onions with thick brown skins, around 3.5lbs 1 quart vegetable stock or broth 2-3 cups water 4 sprigs thyme 1 bay leaf 2 cloves garlic, crushed but not peeled salt to taste 3-4 Tbs butter 3/4 cup red table wine 8-10 oz gruyere, emmenthaler or other swiss-style cheese, with a rind 1/2 a baguette or other European-style bread Equipment: 4qt soup pot, strainer, large dutch oven or large (14") deep saucepan, 4-6 oven-safe ceramic soup bowls, cookie sheet, cheese grater, broiler
First, make the brown onion stock: halve the onions, cut the ends off, and skin them. Dump the clean ends and skins in the stock pot with the veggie stock and the water. Cut the rind off the cheese, peel off any paper/wax, and add it. Add the bay leaf, two of the thyme sprigs, garlic cloves, and a little salt if you feel the stock needs it. Bring to a boil, turn down to low, then simmer for at least one hour while you prepare the onions.
Once the stock is simmering, slice the onions about 1/4" thick. Heat the butter in the dutch oven or deep saucepan until the butter foams, then add the onions. Turn the heat to low and cover for 5 minutes to get the onions started. Caramelize the onions over medium-low heat (uncovered) for 40 to 65 minutes, stirring and scraping the bottom about once every 10 minutes.
Once onions are soft, sweet, stringy, and caramel-colored, deglaze the pot with the wine. Bring to a boil, then strain the stock into the onions. Add the rest of the thyme, stir, correct the salt, and simmer covered over low heat for about 10 minutes.
Heat the broiler. Slice the baguette 1/2 to 3/4 inch thick, and trim slices to mostly fill the top of each bowl. Put the slices on the cookie sheet, and toast them on both sides under the broiler, briefly.
Grate the cheese. Line up the bowls on the cookie sheet, fill each one 3/4 full of soup and onions (do not overfill), and float a toast or two on top, so that most of the surface of the soup is covered. Cover the toasts with a generous helping of the grated cheese.
Place under broiler until the cheese bubbles and starts to brown, 3-5 minutes. Serve immediately, while still bubbling. Serves 4 as a main dish, or up to 8 in smaller ramekins as an appetizer.
Ingredient Notes: Onions need to be brown/yellow onions with thick, dark brown, non-moldy skins. Vegetable stock-in-a-box works fine for this. Quality instant stock or boullion would also work, if it's not too salty. If you don't have fresh thmye, use 1 tsp dried thyme, divided. The wine should be a dry, medium-bodied red that's not too tannic, such as a ligher pinot noir, a merlot, or a mild burgundy. Kaltbach, comte', appanzeller, and several other cheeses will also work for this; the one to stay away from is Jarlsberg, which tends to separate when heated. The bowls you use should be something heavy, ceramic, and oven-safe. Emile Henry bowls, pictured, are the classic.
Failure Modes: if this soup turns out bitter, it is likely because either you burned the onions, the skins were moldy, or you used a wine that was too tannic. Unfortunately, there isn't a good way to rescue a bitter soup. If the soup is too sweet, try adding a little more salt.