If you follow me on Instagram you were able to see this dish as I made it from beginning to end. Thank goodness my teenage daughter showed me how to post to my "story" and "highlights"!
I am posting the step-by-step pictures here, as I always do for my blog. This is a winner of a recipe because it is easy and delicious. Don't worry about exact measurements for squash or spinach, this recipe will work out no matter what proportions you use. Enjoy!
Butternut Squash and Creamed Spinach Gratin
recipe adapted from Gourmet Magazine, November 2006
3 (10-ounce) boxes of fresh baby spinach plus another 6 oz. box (doesn’t
need to be exact – if you only used the three boxes it will be fine)
5 tablespoons unsalted butter plus additional for greasing pan and
topping gratin
1 small onion, finely chopped
3 garlic cloves, minced
1 teaspoon kosher salt (or to taste but be careful not to over
salt!)
1 teaspoon freshly ground black pepper
¼ to ½ teaspoon freshly grated nutmeg
1 cup heavy cream
2-3 pounds butternut squash (1 large or 2 small), peeled and seeded
¼ cup finely grated Parmigiano-Reggiano
Bring 2 cups (or so)
water to a boil in a pot over high heat. Add spinach, a few handfuls at a time,
and cook, turning with tongs, until wilted, about a minute. Remove wilted
spinach to large colander (with plate or shallow bowl underneath to catch
liquid). Continue until all the spinach
is wilted (pouring off liquid from plate as needed). Bring colander and plate over to sink and using
a smaller plate press down on spinach until most of excess moisture has been
removed.
Transfer to a bowl.
Melt 3 tablespoons
butter in an 8-inch heavy skillet over moderately low heat, add onion and
garlic, and about ½ teaspoon of salt and pepper, cook until softened, 3 to 5
minutes. Add onion mixture to spinach along with another ½ teaspoon of salt and
pepper, nutmeg, and cream and stir to combine.
Preheat oven to 400°F.
Butter a 3-quart shallow baking dish (13 by 9 inches; not glass).
Peel and seed the squash
and cut squash to separate bulb section from solid neck section, add to Cuisinart
using slicer blade.
Layer squash and spinach
mixture in baking dish, using about one fifth of squash and one fourth of
spinach for each layer, beginning and ending with squash. Sprinkle top layer of
squash evenly with cheese and dot with remaining tablespoon butter, then cover
directly with a sheet of parchment paper. Bake until squash is tender and
filling is bubbling, about 30 minutes. 
