Some pasta dishes are a breeze to make. Lasagna is not, and there is no getting around it. But it is absolutely worth the effort. Having a companion in the kitchen makes the process go much faster.
That said, this particular lasagna can be achieved more quickly than some of the more elaborate and traditional ones made with a meaty Bolognese ragù or tiny meatballs. My spinach lasagna is composed of Italian fennel sausage, wilted spinach, ricotta, béchamel and Parmesan, which makes for a lighter, more digestible, but still quite luxurious rendition. (I fully expect comments calling this version inauthentic or even blasphemous, but it is delicious.) It is delicate but rich, best served in small portions.
To make the pasta, I whiz raw spinach with eggs in a blender, then mix the bright green liquid with flour to make a soft, easily kneaded emerald-hued dough. As the dough rests, I whisk up a quick béchamel sauce. It’s important to season the béchamel thoroughly with salt and pepper, nutmeg and a tiny pinch of cayenne. It must not be too thick, so be prepared to thin it with milk to the consistency of a milkshake (creamy, but still drinkable through a straw). Keep the sauce warm in a double boiler (it can be makeshift) so it doesn’t thicken upon standing.
You’ll need a full two pounds of fresh spinach to produce bright, leaf-green pasta. If preferred, substitute chard or mustard greens. Combine the greens with ricotta and a bit of grated lemon zest.
Next, roll the pasta dough into thin foot-long sheets. Dust the uncooked pasta sheets lightly with flour to keep them from sticking when stacked. (Of course, you may use store-bought fresh pasta sheets rather than make the pasta yourself, if desired.)
You’ll cook the pasta for only a minute, to keep it undercooked, then cool it in ice water and blot on kitchen towels. When the lasagna is baked, the pasta will cook further, and the result will be perfectly tender.
I find it easiest to cook the pasta in small batches, two sheets at a time, enough to build one layer, then continue to boil two sheets for the next layer, and so on. Once the lasagna is assembled, you may bake it straight away, or keep it refrigerated up to 24 hours. Alternatively, it may be baked well in advance of serving and reheated.