This fusion lasagna can be prepared 12 hours in advance and baked right before serving. It also can be frozen, unbaked. But, though the lasagna can be prepared with any kind of lasagna noodle, if you plan to freeze it before serving, use cooked lasagna pasta sheets or strips. The no-cook and fresh varieties tend to dry out in the freezer. The recipe doubles easily.
- 2 tablespoons vegetable oil (or extra-virgin olive oil)
- 3/4 pound white or button mushrooms, sliced
- 1/2 cup (2 ounces) finely diced onion
- 12 ounces frozen cut-leaf spinach
- 3 cups 2-percent milk, plus more as needed
- 1/2 stick (2 ounces) butter
- 5 tablespoons flour
- Freshly ground black pepper
- Freshly ground nutmeg
- 4 ounces ham, cut into roughly 1/4-inch dice
- 1/2 pound Emmentaler cheese or Gruyere , or a combination of the two, grated
- 3/4 pound fresh, no-cook or cooked lasagna sheets, prepared according to package directions
In a large saucepan, heat 1 tablespoon of the oil over medium-high heat. Add the sliced mushrooms and cook, stirring and tossing the mushrooms, until they just begin to brown and any excess moisture that the mushrooms release has evaporated. Transfer the mushrooms to a large plate or baking sheet to cool.
In the same pan, heat the remaining tablespoon of oil over medium-high heat. Add the onion and cook until it softens, 3 to 4 minutes. Add the frozen spinach and cover the pan. After 2 minutes, remove the lid and stir the spinach. Cover and repeat until the spinach is defrosted. Remove the lid and cook until the moisture from the spinach has evaporated. Transfer the spinach-onion mixture to a large plate or baking sheet to cool.
Heat the milk and set aside.
In a large heavy saucepan, melt the butter over medium heat and stir in the flour. Cook for 1 to 2 minutes, until the mixture starts to thin out, stirring continuously. Add the warm milk in a steady stream while whisking the mixture, to make a bechamel sauce. Add the salt, pepper and nutmeg to taste. Bring to a boil, then reduce the heat to low, letting the sauce simmer slowly for 10 minutes and stirring every few minutes. (The sauce should coat the back of a spoon. If it is too thick, add additional milk to thin it out. It will thicken further when the cheese is added.) Stir in the ham, remove from the heat and add three-quarters of the grated cheese. Stir until the cheese melts and set aside.
To assemble, in a 9-by-13-inch pan, spoon a few tablespoons of the bechamel-cheese sauce. Cover the sauce with a layer of lasagna sheets. Spread the spinach-onion mixture over the first layer, then cover with one-third of the sauce. Add another layer of lasagna sheets and spread the mushrooms over this layer. Cover again with one-third of the sauce. Add the last layer of lasagna sheets, spread the remaining sauce over it, covering the lasagna sheets, and top with the remaining grated cheese.
When ready to bake, preheat the oven to 350 degrees.
Bake uncovered until the lasagna is heated through and the cheese on top is golden brown, 35 to 45 minutes. (If frozen, the lasagna should be baked, covered with aluminum foil, for 45 minutes, then uncovered and baked an additional 30 to 40 minutes or until heated through with the cheese on top golden brown.)
Adapted from former Food section recipe editor Stephanie Witt Sedgwick.
Tested by Stephanie Witt Sedgwick.
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