01 - Preheat the oven to 375°F. Lightly grease a 9x13-inch baking dish with butter or nonstick spray.
02 - Bring a large pot of salted water to a rolling boil. Cook the lasagna noodles according to package directions until al dente. Drain carefully and lay each noodle flat on a lightly oiled baking sheet to prevent sticking.
03 - In a large mixing bowl, combine the shredded chicken, ricotta, mozzarella, Parmesan, minced garlic, parsley, salt, and black pepper. Stir until all ingredients are evenly distributed.
04 - Melt the butter in a medium saucepan over medium heat. Add the minced garlic and sauté for 1 minute until fragrant. Sprinkle in the flour and whisk constantly for 1 minute to form a roux. Gradually pour in the milk while whisking continuously. Bring to a gentle simmer and cook for 3 to 4 minutes, stirring frequently, until the sauce thickens enough to coat the back of a spoon. Remove from heat and stir in the Parmesan, salt, and pepper until smooth.
05 - Spread 1/2 cup of the béchamel sauce evenly across the bottom of the prepared baking dish. Lay each cooked noodle flat and spread 2 to 3 tablespoons of the chicken filling over the surface. Roll each noodle up tightly and place seam side down in the dish, arranging them in a single layer.
06 - Pour the remaining béchamel sauce over the assembled roll ups, ensuring they are well coated. Sprinkle the shredded mozzarella and grated Parmesan evenly over the top.
07 - Cover the dish tightly with aluminum foil and bake for 25 minutes. Remove the foil and continue baking for 10 to 15 minutes, until the cheese is melted, golden, and bubbling throughout.
08 - Remove from the oven and let the roll ups rest for 5 minutes to set. Garnish with additional fresh parsley if desired, then serve warm.