Apply cooking spray on the bottom of a 6-quart oval electric slow cooker. Combine spinach, mushrooms, and pesto in a medium bowl, stirring to combine; set aside. Combine mozzarella, provolone, ricotta, and beaten egg in a medium bowl, stir well. Mix in 1/4 cup Parmesan cheese, and set aside. Combine the pasta sauce and the tomato sauce in a medium bowl.
Spread 1 cup pasta sauce mixture in the bottom. Arrange 3 noodles over pasta sauce mixture; top with 1 cup cheese mixture and 1 cup spinach mixture. Repeat the layers, ending with spinach mixture. Arrange 3 noodles over spinach mixture; top with remaining 1 cup cheese mixture and 1 cup pasta sauce mixture. Place remaining 3 noodles over sauce mixture; spread remaining sauce mixture over noodles. Sprinkle with the remaining 1/2 cup Parmesan cheese. Cover with lid; cook on LOW 5 hours or until done. Makes 8 servings.
Approximate Nutrient Analysis per serving:
400 calories, 17 g fat, 7 g saturated fat, 65 mg cholesterol, 800 mg sodium, 37 g carbohydrate, 3 g fiber, 10 g sugar, 24 g protein