Ingredients for 8 servings

1 large egg
1 small zucchini, quartered lengthwise and thinly sliced
1 5-ounce package baby spinach, coarsely chopped
1 15- to 16-ounce container part-skim ricotta
1 28-ounce can crushed tomatoes
1 28-ounce can diced tomatoes
3 cups shredded part-skim mozzarella, divided
3 cloves garlic, minced
3 large or 4 small portobello mushroom caps, gills removed, halved and thinly sliced
15 whole-wheat lasagna noodles (about 12 ounces), uncooked
Pinch of crushed red pepper (optional)

Directions

Combine egg, ricotta, spinach, mushrooms and zucchini in a large bowl.

Combine crushed and diced tomatoes and their juice, garlic and crushed red pepper (if using) in a medium bowl.

Generously coat a 6-quart or larger slow cooker with cooking spray. Spread 1 ½ cups of the tomato mixture in the slow cooker. Arrange 5 noodles over the sauce, overlapping them slightly and breaking into pieces to cover as much of the sauce as possible. Spread half of the ricotta-vegetable mixture over the noodles and firmly pat down, then spoon on 1 ½ cups sauce and sprinkle with 1 cup mozzarella. Repeat the layering one more time, starting with noodles. Top with a third layer of noodles. Evenly spread the remaining tomato sauce over the noodles. Set aside the remaining 1 cup mozzarella in the refrigerator.

Put the lid on the slow cooker and cook on High for 2 hours or on Low for 4 hours. Turn off the slow cooker, sprinkle the reserved mozzarella on the lasagna, cover and let stand for 10 minutes to melt the cheese.