Every time I try to think of something interesting for Meatless Monday, I invariably come back to pasta. This week was no different, although at least this time I didn't fall back on a tomato-based sauce. It was delicious, although a bit of work—nothing technically difficult, but the kind of recipe that will use up every surface in your kitchen and leave you with plenty of washing up to be done. For the bechamel, you might want to consider borrowing a pan from Ned Flanders and just throwing it away afterward rather than bothering to scrub it. I will definitely make this again. (Oh, and for Wendy and any others who are always hyper-alert to fat content, let it be known that one pan fed all 5 of us with quite a bit left over.)
Spring Shells and Cheese
2 pounds medium zucchini
1 stick (8 tablespoons) unsalted butter
¼ cup all-purpose flour
½ teaspoon freshly grated nutmeg (I forgot to buy this, so I used a pinch of the ground nutmeg I've had in the cabinet since the Clinton era.)
pinch of cayenne pepper
freshly ground black pepper
6 cups whole milk
4 sprigs fresh thyme
3 bay leaves
grated zest of ½ lemon (My only lemon was icky, so I left this out.)
1 pound medium pasta shells
4 shallots, minced
2 large egg yolks, lightly beaten
4 ounces parmesan cheese, grated
4 ounces gruyere cheese, grated (I used a microplane, but it came out too fluffy; next time I will use a regular grater. Or perhaps even a different cheese entirely—one that you can buy already grated!)
4 ounces baby spinach
Grate the zucchini into a colander using the large holes of a box grater. Toss with 1 tablespoon kosher salt, then place in the sink to drain, about 15 minutes. Squeeze out the excess liquid.
Meanwhile, melt 4 tablespoons butter in a large saucepan over medium heat. Add the flour, nutmeg, cayenne, 2 teaspoons kosher salt, and black pepper to taste and mix with a wooden spoon to make a paste. Cook, stirring, until the paste puffs slightly, about 3 minutes. (Mine also turned brownish.) Slowly whisk in the milk, then add the thyme, bay leaves and lemon zest and bring to a boil, stirring. (Keep an eye on it, or else what a mess!) Reduce the heat and simmer until thickened slightly, about 25 minutes. Strain into a bowl; discard the herbs.
Meanwhile, position a rack in the upper third of the oven and preheat to 425°. Bring a large pot of salted water to a boil; add the pasta and cook until al dente, about 8 minutes. Drain and add to the sauce.
Melt the remaining 4 tablespoons butter in a skillet over medium heat. Add the shallots and cook until translucent, 2–3 minutes. Add the zucchini and cook, stirring, until almost tender, about 4 minutes. Add the zucchini mixture to the pasta along with the egg yolks and all but 3 tablespoons of both cheeses; stir to combine, then add the spinach.
Transfer the mixture to a 9-by-13-inch baking dish (it will just barely all fit) and sprinkle with the reserved cheeses. Bake until browned on top and heated through, 25–30 minutes. (Next time I will let it get even browner.) Let rest 10 minutes before serving.