Asparagus Lasagnas

2½ tablespoons extra-virgin olive oil, plus more for greasing the pans

1¾ pounds asparagus, tough ends discarded and stalks peeled when thicker than 1/3 inch

Kosher salt

Freshly ground black pepper

1½ cups finely chopped onion

1 tablespoon minced garlic

2¾ cups part-skim ricotta cheese

1 tablespoon flour

1 tablespoon finely grated lemon zest

18 square won ton wrappers

10 ounces Italian Fontina cheese, coarsely grated

Position an oven rack 4 to 6 inches from the broiler element; preheat the broiler. Use a little oil to lightly grease a rimmed baking sheet and a 9-by-13-inch lasagna pan or jellyroll pan.

Arrange the asparagus in a single layer on the baking sheet; drizzle 1 tablespoon of the oil over it and toss to coat, then season it lightly with salt and pepper. Broil the asparagus for about 5 minutes, shaking the pan several times, until the edges just begin to brown. Let cool; reduce the oven temperature to 375 degrees.

Cook the onion in the remaining 1½ tablespoons of oil in a medium skillet over medium heat, until softened, about 5 minutes. Add the garlic and cook for 1 minute, stirring.

Transfer the onion mixture to a blender, along with the ricotta, flour, lemon zest, ½ teaspoon salt and ¼ teaspoon pepper. Remove the center knob of the blender lid (so steam can escape); puree until fairly smooth.

Cut the cooled asparagus in half crosswise.

Arrange 6 won ton wrappers on the bottom of the lasagna pan, leaving a little space between each one. Arrange half the asparagus on top of the wrappers and top the asparagus with one-third of the ricotta mixture, spreading it evenly, and one-third of the fontina. Put another won ton wrapper on top of each mound (edges lined up or turned to create a diamond shape), and top with the remaining asparagus, half of the remaining ricotta mixture and half of the fontina.

Finally, top with the remaining won ton wrappers, ricotta mixture and fontina. (You can also split the remaining asparagus to create a third layer.)

Roast (upper rack) for about 20 minutes, or until the fontina has melted and the wontons wrappers are golden brown at the edges.

Increase the temperature to broil (with the pan still in the oven); broil the lasagnas for 1 minute, or just until nicely browned on top. Serve right away. Plate with shredded sauteed carrots with crushed red pepper flakes and a squeeze of lemon, or with peperonata - slow-cooked sweet bell peppers with onion, garlic, cherry tomatoes and capers.

Note: You can broil the asparagus and prepare the cheese mixture a day or two in advance, then layer them with the won ton wrappers right before you pop the lasagnas in the oven.

Serves 6

Sara Moulton