Celery Root and Mushroom Latkes with Onion Applesauce

Name: Celery Root and Mushroom Latkes with Onion Applesauce
Ingredients: 1 8-ounce Granny Smith apple; 1 8-ounce onion, unpeeled; 2 teaspoons kosher salt, plus more for seasoning; 1/2 cup chopped fresh cilantro; 1 pound celery root (celeriac), peeled, coarsely grated; 1 pound russet potatoes, peeled, coarsely grated; 1 tablespoon kosher salt; 1 pound washed mushrooms (such as trimmed, halved oyster or chanterelles, or thinly sliced crimini mushrooms); 2 large eggs, beaten to blend; 3 tablespoons all-purpose flour; 1 tablespoon ground cumin; 1 tablespoon ground turmeric; 1 1/2 teaspoons freshly ground black pepper; Vegetable oil (for frying)