Lasagne Verdi al Forno (Baked Spinach Lasagne)

Set oven rack in top third of oven, then preheat oven to 450°. Grease a 9" × 12" baking dish with butter and set aside. Bring a large pot of water to a boil over high heat and add 2 generous pinches of salt. Cook 1 sheet of pasta at a time until it floats to the surface, about 10 seconds. Carefully remove with a slotted spoon and plunge into a large bowl of salted ice water to stop further cooking. Remove from water when cool. Lay sheets out, being careful not to let them touch, on clean, damp kitchen towels and cover with more damp towels.

Line bottom of prepared baking dish with a layer of pasta, trimming sheets with a knife so that they fit in 1 even layer (patch if necessary). Spread evenly with about 1 cup of the meat sauce, then sprinkle lightly with some of the parmigiano. Add another layer of pasta, evenly spread 1 cup of the béchamel sauce on pasta, then sprinkle lightly with parmigiano. Repeat layers (you will have 3 layers of meat sauce and 2 of béchamel), ending with meat sauce and parmigiano. Reserve any extra meat sauce for another use.

Bake lasagne for 10 minutes. Increase oven temperature to 500° and cook until lasagne is bubbling around the edges and browned on top, 5–7 minutes more. Do not overcook. Allow lasagne to rest for 8–10 minutes before serving.