Roasted Butternut Squash Lasagna

Square overhead shot of a plate of butternut squash lasagna

Roasted Butternut Squash Lasagna

A whipped roasted butternut squash sauce layered with sauteed mushrooms, spinach, and three kinds of cheese. It is a rich, meat-free casserole that can be assembled up to two days ahead and baked when you need it.

Course Dinner

Cuisine American, Italian

Keyword butternut squash lasagna, vegetarian lasagna, vegetarian thanksgiving recipes

Prep Time 1 30

Cook Time 40

Resting Time 15

Total Time 2 25

Servings people

Calories 417kcal

Author Blair Lonergan

Ingredients

For the 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

For the 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

For the 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 (you will probably not need the whole box, I use 10 noodles)
1 ½ cups shredded mozzarella cheese
¼ cup grated Parmesan cheese
Optional garnish: chopped fresh parsley or other herbs

Instructions

Preheat oven to 400°F. Grease a deep 13 x 9-inch baking dish and set aside.

Prepare the butternut squash:

Slice the squash vertically down the center and scoop out the seeds. Rub olive oil all over the squash and place the halves cut side down on a parchment lined baking sheet. Roast for 50 to 60 minutes, until a knife slides into the thickest part with no resistance.
Let the squash cool, peel off the skin, and transfer the flesh to a food processor or blender.
Add the milk, thyme, sage, salt, and pepper. Blend until completely smooth, then taste and adjust the seasoning. Set aside.

Prepare the mushrooms:

Melt the butter in a large skillet over medium high heat. Add the onions and saute until soft, about 8 minutes. Increase the heat to high, add the mushrooms, thyme, and sage, and cook until tender and the released liquid has evaporated, about 3 more minutes. Remove from the heat and season with salt and pepper to taste. Set aside.

Prepare the ricotta spinach layer:

Squeeze all of the liquid out of the spinach. A dish towel works best here, and you want to keep wringing until no more water comes out. Place the spinach in a large bowl.
Add the ricotta, mozzarella, Parmesan, egg, salt, garlic powder, and nutmeg. Stir well with a fork to combine.

Assemble the lasagna:

Spread about ¾ cup of the butternut squash mixture across the bottom of the prepared dish. Top with a single layer of no-boil noodles, then half of the ricotta mixture and half of the mushroom mixture.
Add a heaping 1 cup of the squash mixture, another layer of noodles, the remaining ricotta mixture, and the remaining mushrooms.
Spread any remaining squash on top. Finish with 1 ½ cups shredded mozzarella and ¼ cup grated Parmesan.
Cover the dish tightly with foil.
Bake for 25 minutes. Remove the foil and bake about 15 minutes more, until the filling is hot and bubbly and the cheese on top is nicely browned.
Let stand at least 15 minutes before slicing and serving. Garnish with additional chopped fresh herbs if desired.

Notes

Squeeze the spinach completely dry. Frozen spinach holds far more water than it appears to, and it is the most common cause of a runny lasagna.
Roast the squash until very tender. If it does not blend perfectly smooth, it was not roasted long enough.
Cook the mushroom liquid off before assembling, or it will end up in the finished dish.
The egg matters. It sets the ricotta layer so the slices hold together. Omit it for an allergy if you need to, but expect looser slices.
Using regular or homemade noodles instead of no-boil? Boil regular noodles first, and reduce the oven temperature to 375°F for either.
Cover with foil for the first 25 minutes. This steams the no-boil noodles tender and keeps the squash sauce from drying out on top.
Rest for at least 15 minutes before cutting so the cheese sets.
To make ahead: Assemble without baking, wrap tightly in plastic wrap and foil, and refrigerate up to 48 hours or freeze up to 3 months. You can also roast and puree the squash a day early and assemble the next day.
To bake from the fridge: Bring to room temperature on the counter for 30 to 60 minutes first.
To bake from frozen: Bake covered at 400°F for 1 hour, then uncover for 10 to 15 minutes more.
To store: Refrigerate leftovers in an airtight container 3 to 4 days, or freeze up to 3 months.
To reheat: Cover loosely with foil and warm in a 350°F oven about 30 minutes. Individual slices reheat in the microwave in 30 to 60 seconds.
Cooking for two? Divide between two 8-inch square dishes, bake one and freeze the other. Baking instructions stay the same.
Substitution: Small curd or whipped cottage cheese works in place of ricotta. Strain it if watery, and cut back slightly on the salt.

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