This Lasagne with Chard, Spinach and Hazelnuts can be put together well in advance – even the day before – then baked when you are ready to eat, but hold back on the hazelnuts: sprinkle those on top just before you put the lasagne into the oven.
- 2 tablespoon extra-virgin olive oil
- 1 Swiss chard (leaves and stems separated, leaves roughly chopped, stems finely sliced)
- kosher salt (as needed)
- ½ pound baby spinach
- water (as needed)
- freshly ground black pepper (as needed)
- 2 ounce fresh Italian parsley (leaves and stalks roughly chopped)
- 2 ounce fresh dill (leaves and stalks roughly chopped)
- 3 tablespoon unsalted butter
- 2 cup whole milk (gently warmed) plus a splash more if needed
- ¼ cup all-purpose flour
- 4 cup finely grated Parmesan cheese (divided)
- 1 cup finely grated Gruyere cheese
- cooking spray (as needed)
- 1 ½ cup good quality tomato sauce (divided)
- 12 sheets dried lasagne noodles (cooked until al dente and set aside in a single layer on a greased baking sheet)
- 2 ½ ounce chopped hazelnuts
Prepare the greens: Heat olive oil in a large pot with a lid set over medium-high heat. Add the chard stems, caraway seeds, and ¼‑teaspoon salt. Cook stirring occasionally until softened, about 5 minutes. Add half the chard leaves, cook for one to two minutes, stirring, until they wilt, then add the rest of the leaves and stir until wilted. Add the spinach and another ¼‑teaspoon salt and cook, stirring occasionally until well wilted, about 8 minutes. Add a splash or two of water and a couple big grinds of black pepper and turn the heat to low, cover the pot and cook for 10 minutes. Remove from heat and stir in the chopped herbs and season generously with salt. The mix should be a little wet but not at all soupy. Drain off some moisture if needed. Set aside.
Make the Mornay sauce: Heat butter in a medium saucepan over medium heat until foamy. Sprinkle flour over and cook, whisking constantly, 1 minute. Gradually whisk in warm milk. Bring mixture to a boil, reduce heat, and simmer, whisking often, until sauce is thickened and no longer feels grainy when rubbed between your fingers, 6 to 8 minutes. Remove from heat and add 2 cups grated Parmesan, whisking until cheese is melted and sauce is smooth. Remove from heat and set aside in a warm place.
Prepare the lasagne: Preheat the oven to 375 degrees F.
In a medium bowl toss the remaining 2 cups grated Parmesan with the grated gruyere. Set aside.
Use cooking spray to lightly coat a 11x13 shallow baking dish. Drizzle ½ cup tomato sauce onto the bottom, swirl the dish to get the bottom well covered. Cover the base, crosswise, with four sheets of al dente lasagne. Drizzle ½ cup of tomato sauce on top, then spread half the greens over the sauce.
Gently reheat the mornay sauce, using a splash or two of milk if necessary to get it moving in the pan. Dollop half the mornay sauce evenly across the greens, then scatter with ⅓ of the grated cheese mixture. Repeat this process with 4 more sheets of pasta, the remaining ½‑cup tomato sauce, the remaining greens, the remaining mornay sauce, and half of the remaining grated cheese mixture. Finish by topping the lasagne with the final 4 lasagna sheets and the last of the grated cheese mixture. Sprinkle over the hazelnuts, cover the baking dish with foil and bake for 25 minutes then remove the foil and finish cooking 15 to 20 more minutes until bubbling and golden brown. Remove from oven and allow to rest 10 to 20 minutes before serving.