What Type of Mushrooms Should I Use?
For a full-flavored, umami-rich soup, we use a combination of dried porcini mushrooms and assorted fresh mushrooms (such as cremini, portobello, shiitake and button). Porcini mushrooms are wild mushrooms foraged from forests where pine, hemlock and oak trees grow. They have a meaty flavor similar to shiitake mushrooms but are not quite as sharp. Dried porcini mushrooms are available in most places where dried mushrooms are sold, or you can find dried porcini online. Read more about porcini mushrooms and why they add so much flavor to any meal.
Ingredient Spotlight: Porcini Mushrooms
Dried porcini mushrooms are a key ingredient, providing two elements to the soup. First, the dried mushrooms are soaked in 2 cups of boiling water until softened. The soaking liquid is full of flavor, so don’t throw it out. It’s added to the base of the soup, giving it a boost of umami and depth. Then the rehydrated mushrooms are added to the soup along with the assorted fresh mushrooms, which lend an earthy and rich mushroom flavor.
How to Thicken the Soup
Puréeing only some of the slow-cooker mushroom soup gives the dish a complex texture and thickens the soup slightly. We transfer 2 cups of the soup to a blender, blend it until smooth and then add the puréed soup back to the slow cooker. If you want a thicker soup, feel free to blend more than 2 cups. If you don’t have a countertop blender, you can use an immersion blender to thicken the soup.
How to Store Slow-Cooker Mushroom Soup with Sherry
This soup can be stored in an airtight container and refrigerated for up to 3 days. To reheat, you can microwave the soup on High until warm.
Additional reporting by Jan Valdez
Pour 2 cups of the boiling water over the porcini mushrooms. Let stand 20 minutes. Drain the porcini mushrooms in a colander over a bowl, reserving the mushroom broth; set the mushrooms aside. Strain the mushroom broth through a cheesecloth-lined colander into a bowl; discard the solids. Stir in the cornstarch, soy sauce, salt, pepper and remaining 2 cups boiling water into the mushroom broth; set aside.
Heat the oil in a medium-sized nonstick skillet over medium-high. Add the shallots and garlic; cook, stirring occasionally, until the shallots are soft, 4 to 5 minutes. Add the sherry; bring to a boil, and cook for 30 seconds. Remove from the heat.
Stir together the porcini mushrooms, broth mixture, shallot mixture, fresh mushrooms and thyme in a 5-quart slow cooker. Cover and cook on HIGH until the vegetables are very tender and the flavors blend, about 4 hours. Uncover and cook until slightly thickened, about 20 minutes. Transfer 2 cups of the soup to a blender. Remove the center piece of the blender lid (to allow steam to escape); secure the lid on the blender. Place a clean towel over the opening in the blender lid (to avoid splatters). Blend until smooth, about 10 seconds. Return the puréed soup to the slow cooker; gently stir in the cream. Ladle the soup into bowls, and serve hot.
Multicooker directions: Use the SAUTÉ [Normal] function in place of a nonstick skillet for Steps 5-7, if desired. In Step 8, stir in the porcini mushrooms, broth mixture, shallot mixture, fresh mushrooms and thyme. Lock the lid; turn the pressure valve to “Venting.” Cook on SLOW COOK [More] until the vegetables are very tender and the flavors blend, about 4 hours. Turn off the cooker. Remove the lid; press SAUTÉ [Normal], and cook uncovered, stirring often, until slightly thickened. Turn off the cooker. Transfer 2 cups of the soup to a blender, and blend until smooth. Return the puréed soup to the pot; gently stir in the cream.