Pesto Lasagna with Spinach and Mushrooms

I realized that I hadn't had lasagna in far too long and decided that I needed to adapt this slow-cooker recipe. I'm sure that it wouldn't be bad in the slow-cooker, but I just can't seem to bring myself to do it in there. So here's my oven version.

It's super good. I usually don't like vegetable lasagnas as much as ones with meat (particularly ones with sausage), but the pesto makes this version really tasty.

Pesto Lasagna with Spinach and Mushrooms
A variation on this recipe from Cooking Light

4 cups baby spinach
2 cups sliced cremini mushrooms
1/2 cup pesto
3/4 cup (3 ounces) shredded part-skim mozzarella cheese
3/4 cup (3 ounces) shredded provolone cheese
1 (15-ounce) carton fat-free ricotta cheese
1 large egg, lightly beaten
3/4 cup (3 ounces) grated fresh Parmesan cheese, divided
1 (25.5-ounce) bottle fat-free tomato-basil pasta sauce
1 (8-ounce) can tomato sauce
Cooking spray
1 (9-ounce) package precooked lasagna noodles (16 noodles)

Preheat oven to 375ºF.

Arrange the spinach in a vegetable steamer; steam, covered, 3 minutes or until spinach wilts. Drain, squeeze dry, and coarsely chop. 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, stirring well to combine. Stir in 1/4 cup Parmesan, and set aside. Combine the pasta sauce and the tomato sauce in a medium bowl.

Spread 1 cup pasta sauce mixture in the bottom of a 9x13 baking dish coated with cooking spray. Arrange 4 noodles over pasta sauce mixture; top with 1 cup cheese mixture and 1 cup spinach mixture. Repeat the layers, ending with spinach mixture. Arrange 4 noodles over spinach mixture; top with remaining 1 cup cheese mixture and 1 cup pasta sauce mixture. Place remaining 4 noodles over sauce mixture; spread remaining sauce mixture over noodles. Sprinkle with the remaining 1/2 cup Parmesan.

Cover baking dish with aluminum foil and bake for 50-60 minutes, until hot and bubbly. Remove foil and bake for another 5 minutes, until cheese is melted and started to brown. Let sit for 15 minutes before cutting and serving.