We love this spinach and mushroom lasagna. It keeps incredibly well and might even be better the next day. To keep things easy, we use no-boil lasagna noodles. While we were initially skeptical about using them, we’ve fallen in love with their ease and final texture.
1 tablespoon olive oil
1 medium onion, finely diced
8 ounces cremini mushrooms, chopped, 2 ½ cups chopped
1 garlic clove, finely grated or minced
1 pound (450g) fresh spinach leaves, about 10 cups
15 ounces (425g) ricotta cheese, about 2 cups
2 large eggs, beaten
1 (24oz) jar pasta sauce or 3 cups homemade marinara sauce
12 no-boil oven-ready lasagna sheets or use cooked traditional lasagna noodles
1/2 cup finely grated parmesan cheese (1 ½ ounces)
1 ¼ cups grated mozzarella cheese (5 ounces)
3/4 teaspoon fine sea salt
1/4 teaspoon freshly ground black pepper
Preheat the oven to 350°F (177°C). Grease a 9-by-13-inch baking pan with a little oil.
Heat the olive oil in a large skillet over medium heat. Add onions and mushrooms and cook, stirring occasionally, until the onions become translucent, about 10 minutes.
Add the garlic, spinach leaves, and 1/4 teaspoon of salt. Cook, stirring as needed, until the spinach is bright green and wilted. (Don’t worry about the amount of spinach; it may look like a lot now, but as it cooks, it wilts down considerably. Depending on the size of your skillet, you may want to add the spinach in batches.)
In a medium bowl, mix the ricotta cheese, eggs, 1/2 teaspoon salt, and 1/4 teaspoon pepper until well blended.
Spread 1 cup of pasta sauce over the bottom of the baking pan. Arrange three noodles lengthwise and side-by-side to cover the bottom.
Spread half of the ricotta cheese mixture over the noodles. Sprinkle with a third of the parmesan cheese and a third of the mozzarella cheese. Add half of the spinach mixture and dollop a 1/2 cup of marinara sauce over the spinach.
Add a second layer of noodles, then repeat with the remaining cheese, spinach, and another 1/2 cup of sauce. Finish with a third layer of noodles and top with the remaining sauce, parmesan, and mozzarella cheese.
Loosely cover the lasagna with aluminum foil and bake for 30 minutes. Uncover and bake an additional 10 to 15 minutes until the cheese is bubbly and browned around the edges. For a cheesy golden brown top, slide the lasagna uncovered under the broiler for 1 to 2 minutes.