5 ounces baby spinach or another green you like, roughly chopped
Kosher salt and freshly ground black pepper
3 garlic cloves finely chopped
Red pepper flakes
1 teaspoon dried oregano
1 6-ounce can tomato paste
28 ounce can crushed tomatoes
Handful chopped fresh basil optional
1 pound dried lasagna noodles not no-boil type
2 cups whole milk ricotta
1/4 cup heavy cream optional
1 pound mozzarella coarsely shredded low-moisture
1 cup parmesan finely grated
Equipment
Large frying pan
Large bowl or baking dish
9×13 baking dish
Directions
In a large frying pan, heat 2 tablespoons of the olive oil over medium-high heat. Add the onion and fennel and cook for 8 to 10 minutes, until lightly browned at the edges. Add the mushrooms and cook for 5 minutes, until they’ve softened and any liquid that was released had mostly cooked off. Add the spinach in the last minute, just letting it soften. Season each addition with salt and pepper. Once vegetables are all tender and well-seasoned, scrape them into a bowl.
In the same pan, heat remaining 2 tablespoons olive oil. Add garlic, red pepper flakes, and oregano and cook together for 30 seconds to 1 minute, until the garlic is just barely golden. Add tomato paste and cook for 3 to 4 minutes. Add two cans of water (from the tomato paste) and stir up any stuck bits. Add canned tomatoes, 1 teaspoon salt, and basil. Simmer mixture together for 4 to 5 minutes; adjust seasonings to taste.
Heat oven to 400°F (200°C). Place lasagna noodles in a large bowl or baking dish and cover with the hottest tap water you can get. Soak for 10 minutes. Mix mozzarella and parmesan. Mix ricotta with heavy cream (if using) and season with some salt and black pepper.
Lightly coat a 9×13 baking dish with oil or nonstick spray. Pour 1/3 cup of sauce into the dish and spread it evenly across the bottom. Add a layer of noodles, slightly overlapping their edges. Dollop 1/4 of the ricotta (about 1/2 cup) over noodles and spread it in an even layer. Add 1/4 of the vegetable mixture, then about 1/5 of the mozzarella-parmesan mixture. Pour a scant cup of sauce evenly over cheese. Place next layer of noodles on top. Repeat this process three times, using up all but the mozzarella-parmesan mixture and about 1/3 cup of the sauce. Place final layer of noodles on top, spread remaining sauce thinly over it and scatter the top with the remaining mozzarella-parmesan mixture.
Cover a large tray with foil and place baking dish on top of it. Lightly coat a piece of foil with nonstick spray and tightly cover baking dish with foil, oil side down. Bake for 30 minutes. Remove foil carefully and bake for another 20 minutes, until lasagna is golden on top and bubbling. Let it sit for 45 minutes before serving.