With this modernized recipe, we’re adding barley to a pot of vegetarian soup along with both dried and fresh mushrooms, and seasoning it with a surprising combination of soy sauce and balsamic vinegar. The bowls of soup have a satisfying saltiness and an alluring sweetness—it’s an entirely new take on traditional mushroom barley soup. Mushrooms and barley are an old pairing, popular in dishes around the world wherever mushroom foragers lived. For centuries, Eastern European cooks made versions of this soup as soon as the weather got cold—a simmering pot was on the menu pretty much all winter. I like to use a mix of dried and fresh mushrooms in my soup. Dried mushrooms, especially porcini, add a lot of intense flavor to the pot, while the fresh mushrooms are earthy but mild by comparison. For the fresh mushrooms, I like to use a combination of button, shiitake and large or baby portobello mushrooms, chopping the large ones and slicing small ones so you get a variety of textures. Use pearl barley for this recipe; “pearl” means that the grains have been partially processed to remove the hull and bran, then polished. It cooks faster. Hulled barley, as the name suggests, has been hulled, but the bran is intact, so it takes longer to cook. Just a heads up: the grain continues to expand as they sit in the broth, so if you cook the soup a day ahead and let it chill overnight (which is a good idea because the flavors mellow), you might need to add more water if the mixture seems too thick. I make this soup with plain water so I can build the seasonings myself. I stir in generous spoonfuls of soy sauce and balsamic vinegar—these ingredients, which add an aromatic, umami boost, weren’t available to Eastern European home cooks centuries ago, but why not take advantage of our modern pantries?! With so many things going into the pot, this soup has lots of satisfying bits to nibble and enough heft to serve as a main course. This recipe makes a large batch, plenty for dinner tonight and meals in the days to come. With a slotted spoon, lift the mushrooms out of the bowl and transfer to a cutting board. Coarsely chop them. Strain the soaking liquid through a sieve lined with a paper towel to catch any grit and reserve. Add the mushrooms, stir well, and continue cooking, stirring occasionally, for another 10 minutes. Add the potato and barley and cook, stirring, for 1 minute more. Bring to a boil, then lower the heat. Partially cover and simmer for 45 to 50 minutes, or until the barley and potatoes are both tender. If the mixture seems too thick at any point, add more water, 1/2 cup at a time. Leftovers will keep refrigerated for up to a week, or frozen for up to 3 months.
