Ingredients
Butternut Squash Layer
- 1 large butternut squash (about 3 ½ to 4 pounds)
- 1 to 2 tablespoons olive oil
- ⅔ cup milk
- 1 teaspoon fresh thyme leaves (or ½ teaspoon dried thyme leaves)
- 2 fresh sage leaves (or ¼ teaspoon dried sage)
- ¾ teaspoon kosher salt
- Dash of ground black pepper
Mushroom Layer
- ¼ cup (½ stick) salted butter
- 2 large yellow onions, thinly sliced
- 8 ounces sliced baby bella or white button mushrooms
- ½ teaspoon chopped fresh thyme leaves (or ¼ teaspoon dried thyme leaves)
- 1 fresh sage leaf, chopped (or ⅛ teaspoon dried sage)
- Kosher salt and ground black pepper, to taste
Ricotta Spinach Layer
- 1 (10 ounce) package frozen chopped spinach, thawed
- 15 ounces ricotta cheese (or 16 ounces small curd cottage cheese, extra liquid strained)
- 1 cup shredded mozzarella cheese
- ¼ cup grated Parmesan cheese
- 1 large egg, lightly beaten
- ½ teaspoon kosher salt
- ½ teaspoon garlic powder
- ⅛ teaspoon ground nutmeg
For Assembling
- 1 (12 ounce) package no-boil (“oven ready”) lasagna noodles (about 10 noodles used)
- 1 ½ cups shredded mozzarella cheese
- ¼ cup grated Parmesan cheese
- Optional garnish: chopped fresh parsley or other herbs
Instructions
- Preheat and Prepare Dish: Preheat your oven to 400°F (200°C). Grease a deep 13 x 9-inch baking dish and set it aside to prepare for layering the lasagna.
- Roast the Butternut Squash: Slice the squash vertically down the center and scoop out the seeds. Rub olive oil over the cut sides and place the halves cut side down on a parchment-lined baking sheet. Roast for 50 to 60 minutes until tender when pierced with a knife. Cool, peel, and transfer the flesh to a food processor.
- Make Butternut Squash Puree: Add milk, thyme, sage, salt, and pepper to the squash in the processor and blend until completely smooth. Taste and adjust seasoning as needed, then set aside.
- Prepare Mushroom Mixture: Melt butter in a large skillet over medium-high heat. Add the sliced onions and sauté until soft, about 8 minutes. Increase heat to high, add mushrooms, thyme, and sage, and cook until mushrooms are tender and moisture evaporates, about 3 minutes. Season with salt and pepper, remove from heat, and set aside.
- Make Ricotta Spinach Mixture: Thoroughly squeeze liquid from thawed spinach using a dish towel. In a large bowl, combine spinach, ricotta, mozzarella, Parmesan, beaten egg, salt, garlic powder, and nutmeg. Stir well to create an even mixture.
- Assemble the Lasagna: Spread about ¾ cup of the butternut squash puree evenly over the bottom of the prepared baking dish. Layer with a single row of no-boil noodles, then half of the ricotta spinach mixture followed by half of the mushroom mixture. Next, spread a heaping 1 cup of squash puree, add another noodle layer, then the remaining ricotta mixture and mushrooms. Top with remaining squash puree.
- Add Cheese and Bake: Sprinkle 1 ½ cups shredded mozzarella and ¼ cup grated Parmesan over the top. Cover the dish tightly with foil and bake at 400°F for 25 minutes. Then remove the foil and bake an additional 15 minutes until the filling is bubbly and the cheese is golden brown.
- Rest and Serve: Let the lasagna stand for at least 15 minutes before slicing. Garnish with chopped fresh parsley or herbs if desired and serve warm.
Notes
- Make sure to squeeze out as much water from the spinach as possible to prevent a watery lasagna.
- Use no-boil or oven-ready lasagna noodles to simplify assembly and avoid pre-cooking noodles.
- Fresh herbs can be substituted with dried if fresh are not available; adjust quantities accordingly.
- Letting the lasagna rest after baking allows the layers to set for easier slicing.
- Leftovers keep well refrigerated for up to 3 days and can be reheated in the oven or microwave.
- Prep Time: 30 minutes
- Cook Time: 1 hour 40 minutes
- Category: Main Course
- Method: Baking
- Cuisine: Italian
- Diet: Vegetarian
