2 tablespoons chopped basil leaves, plus more to top
2 cups cooked, shredded chicken
2 cups ricotta cheese
Place the lasagna noodles in a casserole dish, stacking them in alternating directions. Pour boiling water over the noodles and let them soak in the hot water until softened, pliable, but not sticky, about 20 minutes, and then drain.
While the noodles soak, place the spinach in a large pot over medium heat. Cover and cook for 2 minutes. Uncover, toss the spinach, and cover again. Cook until the spinach is wilted, about 2-3 more minutes. Transfer the spinach to a colander and let cool.
Place the pot back on the heat and add melt the butter in it. Add in the onion and garlic and saute until softened, stirring often, about 5 minutes. Mix in the flour and stir together until the mixture begins to brown and thicken. Slowly stir in the chicken broth and milk.
Bring the mixture to a boil and continue to stir, gently scraping the bottom to prevent the flour mixture from burning onto the pot. Once thickened and smooth, reduce the heat to low. Mix in 2 cups of the mozzarella cheese and 1/2 cup of the parmesan. Season with salt and pepper, to taste, and mix in the chopped basil.
Keep the mixture warm over low heat and preheat the oven to 400 degrees F.
Press the excess water out of the wilted spinach, making sure to get as much out as possible. Place the spinach in a medium-sized mixing bowl. Add in the shredded chicken, ricotta, 1 cup of mozzarella, and 1/2 cup of the parmesan. Mix well to combine.
Spread the chicken and cheese filling in an even layer over each noodle, and then roll up the noodles to enclose the filling.
Spoon half of the white sauce into the bottom of a square baking dish. Press the lasagna rolls, one at a time, into the white sauce. I like to put mine in so that the swirled side is facing upward, but you can also place them seam-side down if you’d prefer.
Once all of the rolls are arranged in the baking dish, spoon the remaining white sauce on top. Cover with the remaining cheese.
Bake until golden and bubbly, about 30 minutes. Top with fresh basil and serve warm.