Vegan Mushroom Barley Soup

Name: Vegan Mushroom Barley Soup
Ingredients: 1 ounce dried porcini or other dried mushrooms; 2 cups hot tap water; 1 1/2 pounds fresh mushrooms (button, shiitake, large or baby portobello, or a mix); 3 tablespoons olive oil; 1 clove garlic , minced; 1 large onion , diced; 2 ribs celery , diced; 2 carrots , diced; 1 teaspoon salt; 1/2 teaspoon black pepper; 3/4 cup pearl barley; 1 medium Yukon Gold potato , cut into 1/2-inch chunks; 8 cups water , plus more if needed; 2 tablespoons soy sauce , plus more to taste; 2 tablespoons balsamic vinegar , plus more to taste; 1 bay leaf; 1/4 cup chopped fresh parsley; 1/4 cup chopped fresh dill; 3 ounces baby spinach (2 cups packed), tough stems removed