Caramelized Onion, Mushroom, & Spinach Lasagna is delicious, light and easy to make! It is the perfect light and healthy meal for lunch or dinner, and great for vegetarians. Serve with a Classic Italian salad.
Each layer in the Caramelized Onion, Mushroom, & Spinach Lasagna is a star in this dish. The caramelized onions are deglazed with balsamic vinegar and pair perfectly with the creamy ricotta cheese. The sautéed mushrooms and wilted spinach are nestled with shredded mozzarella cheese for the second layer. The top layer is more sauce and freshly grated Parmesan cheese. Assemble the lasagna with no-boil lasagna pasta sheets and store-bought marinara sauce to speed up the process. Cook the fresh vegetables in the same skillet to minimize cleanup. I made the lasagna pictured here with a spicy Arraribiata Sauce instead of classic Marinara. We just like the the extra flavor. That is up to you.
Here is the step-by-step guide:
Gather your ingredients and prepare each layer. First sautee mushrooms in olive oil and butter with a little thyme. Transfer to a plate and Set aside to cool.
Sautee fresh, chopped spinach in olive oil with a some grated nutmeg, salt and pepper until just wilted. Transfer to a plate and set aside to cool.
Make the caramelized onions. Sautee raw, sliced sweet onions in the same skillet with lots of butter and olive oil.
Cook for about 20 minutes over medium heat until golden brown and slightly crisped on the edges.
Deglaze the pan with balsamic vinegar, and cook for 2 more minutes until thick and luscious.
Prepare the ricotta cheese filling. Mix ricotta cheese, an egg, Parmesan and Romano cheese until well combined. Season with black pepper and nutmeg.
Assemble the lasagna in a 10 x 14 inch lasagna pan. To make the first layer, place some Marinara sauce on the bottom of the pan. Add a layer of no-boil noodles. Top with the Ricotta cheese filling. Place the Caramelized Onions on top of the ricotta filling.
Make the second layer of the lasagna. Add a layer of no-boil noodles on top of the onions. Cover the noodles with more Marinara sauce. Spread the sautéed mushrooms over the sauce. Sprinkle shredded mozzarella cheese over the mushrooms. Place the wilted spinach over the mozzarella cheese.
Finish with the top layer. Add a layer of no-boil pasta noodles. Cover with more Marinara sauce. Generously sprinkle the remaining Parmesan Cheese on top.
Cover with foil and bake at 375 degrees for 45 -55 minutes. Remove the cover during the last 10 minutes to brown the top.
Allow to cool for about 10 minutes and cut in slices with a sharp knife. Serve with extra Marinara and grated cheese on the side.
Caramelized Onion, Mushroom, & Spinach Lasagna
Ingredients
Cheese Filling
- 32 ounces ricotta cheese
- 1 egg
- 1 cup freshly grated parmesan cheese
- ½ cup freshly grated romano
- 1 teaspoon freshly grated nutmeg
- 1 teaspoon ground black pepper
Caramelized Onions layer
- 2 tablespoons butter
- 2 tablespoons olive oil
- 2 large sweet onions sliced
- ½ teaspoon salt
- ½ teaspoon black pepper
- 1-2 tablespoons balsamic vinegar
- Pinch red pepper flakes optional
Mushroom layer
- 16 ounces white crimini mushrooms sliced
- 1 tablespoon butter
- 1 tablespoon olive oil
- 1 sprig thyme leaves strippped of stem
- ½ teaspoon salt
- ½ teaspoon black pepper
Spinach layer
- 12 ounces fresh spinach washed and rough chopped
- 1 tablespoon olive oil
- 1/8 teaspoon freshly grated nutmeg
- ½ teaspoon Kosher salt
- ½ teaspoon ground black pepper
Final Assembly
- 12 - 16 ounces no-boil lasagna sheets enough to fit 3 layers in a 10 x 14 pan
- 10 ounces mozzarella cheese shredded
- 24 ounces good quality fresh Marinara (or Arrabbiata sauce), store bought or homemade
- ¼ cup parmesan cheese for top
Instructions
- Preheat oven to 375 degrees. Spray a 10x14 inch casserole dish with cooking spray or grease with olive oil.
To make the ricotta filling
- In a medium bowl, mix ricotta cheese, parmesan and romano cheeses, nutmeg, and pepper together until well combined. Set aside
To make the Caramelized Onions
- Heat butter and olive oil on high heat in a large skillet. Add the sliced onions and cook on high heat for about 10 minutes, constantly stirring with spatula. Reduce heat to medium and continue cooking for 10 more minutes. Keep stirring to prevent burning on the bottom. Cook for 10 more minutes or until the onions are a deep golden brown. Add the balsamic vinegar to deglaze the pan. Transfer the mixture to a plate to cool.
Prepare the Spinach
- Add 1 tablespoon olive oil to large skillet over medium high heat. Add freshly washed and chopped spinach, nutmeg, salt and pepper and toss. Cook for 5 -7 minutes or until just wilted. Set aside to cool.
Prepare Mushrooms
- Heat olive oil on high heat in a large skillet. Add the sliced mushrooms, salt, thyme, black pepper (and red pepper flakes if using) and mix. Cook on medium high heat for about 10 minutes, stirring occasionally to prevent sticking, until golden brown. Transfer to a plate to cool.
To assemble the casserole
- Make first layer: Place ½ cup marinara on bottom of prepared 10 x 14 baking pan. Add one layer of lasagna sheets. Spread all of ricotta mixture over the lasagna sheets. Spread all of the carmelized onions on top of the ricotta layer.Make second layer: Add half a layer of noodles on top of the onions. Add ¾ cup marinara sauce over noodles. Place mushrooms evenly over the sauce. Sprinkle with handfuls of mozzarella cheese. Place cooked spinach evenly on top of mozzarella cheese. Sprinkle rest of mozzarella over spinach.Make top layer: Add layer of noodles on top of second layer. Spread rest of marinara sauce evenly over the top of the noodles. Sprinkle the top with parmesan cheese.
- Cover the pan with foil. Bake at 375 degrees for 45 - 55 minutes or until the top is golden brown and the sides are bubbling. If needed, remove the foil from the pan the last 10 minutes to brown the top.
- Remove from oven and allow to cool for 10 minutes.Cut in squares and serve immediately with extra Marinara on the side.
Oh, this one is a keeper. All the guests tonight raved about the flavors, some claiming it’s the best lasagne they’d ever had.
Baking at nearly 5000ft did cause me a bit of trouble, in that not all of the pasta cooked through. I will know next time to cook longer than the recipe (I had it in 55 minutes but that was not quite enough).
It was a project, though next time I know it will be easier. I did prep everything ahead of time, as you suggest, which made a BIG difference in moving from onions to spinach to mushrooms, LOL.
I’m dying to upload my pix here but it seems alas I cannot. You’ll have to imagine how good it was.