What a difference a few drops of vinegar make. I sat down to eat my soup and couldn’t shake the thought that it was missing something. It seemed like enough salt, but I thought maybe if I dribbled in some umami-y soy sauce, that would do the trick. On the way to the cabinet, I saw the bottle of sherry vinegar that I’d put on the counter to add to the soup and forgotten about it. It turns out, that’s exactly what the soup needed.
It isn’t that the soup is so bad without it, not by any means. With a flavor base of browned onions and carrots, then garlic and tomato paste, and finally a pile of sliced fresh mushrooms, there’s plenty of sweet and meat flavors (although no actual meat). A pinch of truffle salt didn’t hurt matters either, and porcini mushrooms along with their rehydrating broth take the mushroominess up another notch.
Farro gives the soup substance, and altogether it adds up to a dark, deeply flavored soup that is, nonetheless, missing something. A spoonful of sherry (or red wine) vinegar adds a touch of brightness that balances the rich flavors of the mushrooms. And then the soup is just right.
I added a stalk of celery too, because I had some in the fridge. I wouldn’t buy it just for this recipe though.
Feel free to substitute barley or wheat berries for the farro, but you’ll need to adjust the cooking time for different grains.
The photos of the final soup are of leftovers. Overnight, the farro soaks up some of the broth, making a thicker soup with softer grains. The soup is wonderful fresh, but I might even prefer it leftover.
¼ ounce dried porcini mushrooms, rinsed
1 tablespoon olive oil
1 medium onions, diced fine
1 medium carrot, diced fine (or 1 carrot and 1 stalk of celery)
2 cloves garlic, minced
2 teaspoons tomato paste
1 pounds cremini mushrooms, sliced ⅛-inch thick
¼ cup sherry
2 cups broth (I prefer chicken)
½ cup farro, rinsed
Salt and black pepper
2 teaspoons sherry vinegar
1. Place the dried mushrooms in a small bowl with ½ cup water; cover the bowl with plastic wrap, use a paring knife to make about 5 holes in the plastic wrap, and microwave on high for 30 seconds. Set aside for 10 minutes to let the mushrooms soften. Use a fork to lift the softened mushrooms out of the liquid. Mince the mushrooms and strain the liquid through a coffee filter to remove grit, reserving the strained liquid. (This is the official method; I never do it this way, I just let the grit settle to the bottom of the liquid and leave the bit of gritty liquid behind when I use the liquid later in the recipe.)
2. In a large saucepan, heat the oil over medium heat. Add the onions and carrots and cook, stirring occasionally, until the onions just start to brown around the edges, about 8 minutes. Add the garlic and tomato paste; cook, stirring constantly, until fragrant, about 30 seconds.
3. Add the fresh mushrooms; cook, stirring occasionally, until they release their liquid, 3-5 minutes. Increase the heat to medium-high and cook until the liquid evaporates and the mushrooms just begin to brown, about 10 minutes. Add the sherry; scrape up any browned bits on the bottom of the pan. Add the broth, farro, minced porcini, the liquid leftover from soaking the mushrooms, 2 teaspoons salt, and ½ teaspoon pepper. Bring to a simmer over high heat, then reduce the heat to medium and simmer for about 40 minutes, until the farro is tender. (The soup can be stored at this point for up to 5 days. Heat on the stove over medium heat just before serving.) Stir in the sherry vinegar. Add more salt and pepper if necessary; serve.