Spinach and Mushroom Lasagna
Vegetable oil spray
8 curly-edged lasagna noodles (7 ounces), broken in half
Salt and pepper
1 tablespoon extra-virgin oil
1½ pounds white mushrooms, trimmed and sliced thin
2 garlic cloves, minced
20 ounces frozen spinach, thawed, squeezed dry, and chopped coarse
1 (15-ounce) jar alfredo sauce
1¾ cups ricotta cheese (15 ounces)
1¼ cups grated Parmesan cheese (2½ ounces)
½ cup minced fresh basil
1 large egg
4 cups shredded mozzarella cheese (1 pound)
1. Line slow cooker with aluminum foil collar, then line with foil sling and coat with vegetable oil spray. Bring 4 quarts water to boil in large pot. Add broken lasagna noodles and 1 tablespoon salt and cook, stirring often, until al dente. Drain noodles, rinse under cold water until cook, then spread out in single layer over clean kitchen towels and let dry. (Do not use paper towels; they will stick to noodles.)
2. Heat oil in pot over medium-high heat until shimmering. Add mushrooms, garlic, and ¼ teaspoon salt, cover and cook until mushrooms are softened, about 5 minutes. Uncover and continue to cook until mushrooms are dry and browned, 5 to 10 minutes longer. Stir in spinach and alredo sauce, scraping up any browned bits, and season with salt and pepper to taste.
3. In bowl, mix ricotta, 1 cup Parmesan, basil, egg, ½ teaspoon salt, and ½ teaspoon pepper together. Spread ½ cup mushroom spinach sauce into prepared slow cooker.
4. Arrange 4 lasagna noodle pieces in slow cooker (they may overlap), then dollop 9 rounded tablespoons of ricotta mixture over noodles. Sprinkle with 1 cup mozzarella, then spoon 1 cup more mushroom-spinach sauce over top. Repeat layering of lasagna noodles, ricotta mixture, mozzarella, and mushroom-spinach sauce twice more.
5. For final layer, arrange remaining 4 noodles in slow cooker, then top with remaining mushroom-spinach sauce and sprinkle with remaining mozzarella and remaining Parmesan. Cover and cook until lasagna is heated through, about 4 hours on low.
6. Let lasagna cool for 20 minutes. Using sling, transfer lasagna to serving platter and serve.