Potato-Spinach Casserole with Trumpet Mushrooms - Forks Over Knives

Ingredients

• 2 lb. Yukon Gold potatoes, scrubbed and sliced into ⅛-inch- thick rounds (about 8 cups)
• 2 cups chopped yellow onion
• 2 cups chopped fresh trumpet mushrooms
• 4 teaspoons garlic powder
• 2 teaspoons dried thyme, crushed
• 4 cups fresh or frozen spinach, chopped
• Sea salt, to taste
• Freshly ground black pepper, to taste
• 7 oz. extra-firm tofu, drained and grated on the large holes of a box grater (1 cup)
• 2¾ cups unsweetened, unflavored plant-based milk
• ½ cups chickpea flour
• 1 cup brown rice flour
• ½ cup nutritional yeast
• 1½ teaspoons baking powder
• 1 teaspoon black salt or sea salt
• ¼ teaspoon ground turmeric
• ¼ teaspoon freshly ground black pepper