Spinach Lasagne with Butternut Squash & Mushrooms

From the blog For Love of the Table

1 to 1 1/4 lb. Butternut squash, peeled, halved lengthwise, seeded and cut cross-wise into 1/4-inch thick slabs

2 T. olive oil, divided

Salt & freshly ground pepper, to taste

3 1/2 T. butter, divided

8 oz. crimini or white mushrooms, sliced 1/4-inch thick

1 medium shallot (about 1 1/2 oz.), peeled and minced

1/4 c. dry white wine

1 lb. baby spinach, washed

1 c. (240 g) whole milk ricotta

1 oz. (1/3 c) finely grated Parmesan

1 clove garlic, finely grated with a microplaner or smashed to a purée with a pinch of salt

Pinch nutmeg

1 1/3 c. whole milk

2 T. flour

6 oz. Fontina or Fontal, coarsely grated

8 "no-boil" lasagna (half of an 8 oz. box)

In a large bowl, toss the squash with a tablespoon or so of olive oil (enough to lightly coat all the squash) and season with salt and pepper. Spread in a single layer on a baking sheet and roast in a 450° oven until tender and caramelized—about 25 to 30 minutes. (Flip the squash over about 2/3 of the way through for more even browning.) Set aside when done.

While the squash roasts, place the spinach in a large stock pot with just the water clinging to the leaves from washing (or—if you have purchased a container of triple washed, add about a quarter inch of water to the pan before adding the spinach). Cover the pot and set over high heat. When you hear the water begin to boil and steam, uncover and turn the spinach over and over in the pot (using tongs) until it has all collapsed. This whole process should only take a minute or two. Dump the contents of the pot into a strainer of colander to get rid of most of the water. Spread the spinach on a sheet pan and let cool. When cool, squeeze out the excess water a handful at a time. Chop the spinach medium fine. You should have 1 1/4 to 1 1/3 cups loosely packed chopped spinach. Set aside.

While the squash roasts and the spinach cools, melt a tablespoon of butter with a tablespoon of olive oil in a wide sauté pan set over moderately high to high heat. When the butter stops sputtering and the foam subsides a bit, add the mushrooms. Sauté the mushrooms (tossing or stirring occasionally) until tender and golden and any liquid released has evaporated. (Season the mushrooms with salt when they have begun to take on some color.) Reduce the heat under the mushrooms to medium/medium-low. Push the mushrooms out towards the perimeter of the pan and add another tablespoon of butter to the center of the pan. When the butter has melted, add the shallots and a pinch of salt and cook until tender and fragrant...this will just take a few minutes. Add the wine to the pan, increase the heat slightly. Allow the wine to reduce completely to a buttery glaze, scraping the bottom of the pan occasionally get all of the caramelized mushroom juices. Taste and correct the seasoning. Set aside.

Place the ricotta, parmesan, garlic, spinach and a pinch of nutmeg in a medium-sized bowl. Mix until well combined, seasoning to taste with salt and pepper.

Prepare the béchamel: In a small saucepan, bring the milk to a simmer; keep hot. (Alternatively, heat the milk in a microwave proof container of some kind.) In another medium saucepan, melt 1 1/2 T. of butter over medium heat. When the foam subsides, whisk in the flour. Cook stirring constantly for a minute or so—the roux will be bubbly and straw yellow. Remove from the heat and pour in half of the hot milk, whisking constantly until smooth—it will thicken immediately. Add the remaining milk. Return to the heat and stir constantly until the sauce returns to a simmer. Taste and season as desired with salt and pepper.

When you are ready to build the lasagne, oil a square 2-quart baking dish (an 8 1/2- by 8 1/2-inch Pyrex is perfect) and bring a shallow pan of water just to the boil and remove from the heat. Arrange these two items...along with all the other components—on your work space so that you have easy access to everything. Add two of the noodles to the pan of hot water. Spread a couple of tablespoons of béchamel in the bottom of the oiled dish. Lift the noodles out of the pan. (They should not be soft or flexible at this point...you're just giving them a head start by soaking them briefly—less than a minute.) Let the excess water drip back in to the pan and arrange them in a single layer in the prepared baking dish. Add a couple more noodles to the pan of hot water (to soak while you build the first layer). Scatter a third of the mushrooms and a third of the squash over the noodles. Daub a third of the ricotta mixture over the vegetables, spreading it out a bit using two forks. Drizzle a fourth of the remaining béchamel (about 1/3 cup) over the ricotta-spinach mixture (spreading if a big glob goes all in one place). Scatter a quarter of the Fontina (1 1/2 oz.) over all. Beginning with the noodles, repeat this layering two more times. Finish with two more (soaked) noodles, the remainder of the béchamel (spreading evenly) and a scattering of the remaining Fontina (1 1/2 oz.).

Cover the pan with a piece of aluminum foil that has been brushed on the underside with olive oil (or sprayed with pan spray), tenting the foil slightly if possible so that it isn't touching the top of the lasagne. Bake in a 350° oven until the cheese on top has just melted—about 25 to 30 minutes. Uncover and continue to bake until the lasagne is bubbling around the edges and the top is beginning to brown around the edges...another 10 to 15 minutes. Let the lasagne rest for 5 to 10 minutes. Cut with a sharp knife and serve. Serves 4 to 6.

Notes:

The amounts of mushrooms and squash will seem very skimpy as you are building the lasagne. This is as it should be.
The ricotta-spinach mixture may seem very stiff (depending on the moisture in your ricotta). Don't worry if it won't spread into an even layer—it is in fact very likely that it will not. Just daub it evenly over the vegetables and flatten it a bit with a fork. It will spread out—or at least give the impression of having spread out—as it bakes.
I have never made this with frozen spinach, but I imagine that frozen chopped spinach—thawed and squeezed dry and measured to make 1 to 1 1/3 cup would be fine.
Substitute Low-moisture Mozzarella for the Fontina/Fontal if you like.
This makes a tall lasagne...so if you double the lasagne, it would be best to go with a 15- by 11-inch pan rather than a 13- by 9-inch.

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As published on forloveofthetable.com