4 dry lasagna noodles
2 tablespoons unsalted butter, plus more for coating the baking dish
1 clove garlic, minced
1/2 cup heavy cream
1/4 cup grated Parmesan cheese
1 teaspoon lemon juice
Freshly ground black pepper
1/2 cup cooked shredded chicken
1/2 cup loosely packed baby spinach leaves
3/4 cup shredded mozzarella cheese
Arrange a rack in the middle of the oven and heat to 350°F. Lightly coat a 9x9-inch baking dish with butter; set aside.
Bring a large pot of salted water to a boil. Add the lasagna and cook according to package directions until al dente. Transfer to a clean towel and lay on a flat surface to dry and cool.
Meanwhile, make the sauce: Melt the 2 tablespoons butter in a small saucepan over medium heat. Add the garlic and sauté until fragrant, about 1 minute. Add the cream, bring to a simmer, and cook, stirring frequently, until the sauce thickens slightly, about 5 minutes. Remove from the heat and add the Parmesan, lemon juice, a big pinch of salt, and a few grinds of pepper. Whisk until smooth and set aside.
Combine the chicken, spinach, 1/2 cup of the mozzarella, and 1 tablespoon of the sauce in a large bowl. Divide the mixture among the lasagna noodles and spread into an even layer. Starting from a short end, roll up the noodles into a tight roll. Place the roll-ups seam-side down, side by side and touching in the baking dish.
Pour the remaining sauce over the roll-ups, and sprinkle the remaining 1/4 cup mozzarella over the top. Bake until heated through and the sauce is bubbling, 15 to 20 minutes.