Recipe: Gingery Tofu Slow Cooker Soup

Name: Recipe: Gingery Tofu Slow Cooker Soup
Ingredients: 3 1/2 ounces fresh shiitake mushrooms, scrubbed; 1 medium lemon; 8 cups (2 quarts) water; 1 medium carrot, cut crosswise into 3 pieces; 1 (1-inch) fresh ginger, peeled and cut into 1/4-inch thick slices; 1 medium scallions, cut crosswise into 3 pieces; 1 tablespoon kosher salt; 1/8 teaspoon ground turmeric; 3 1/2 ounces baby bok choy, sliced 1/4-inch thick (about 1 1/2 cups); 1 pound firm tofu, cut into 1/4- to 1/2-inch cubes; 4 ounces dry soba noodles; Options for serving: thinly sliced scallions, fresh cilantro leaves