Preheat oven to 375°F. Spray a 9x11 inch baking dish with cooking spray.

Cook lasagna noodles according to package for al dente; drain and set aside.

Meanwhile, add squash to a medium skillet and add an inch of water. Heat over medium-low for about 10 minutes or until fork tender; let cool slightly. Add squash to blender and puree until smooth, adding water from skillet as needed.

Melt butter in a separate saucepan over medium heat. Whisk in flour until no longer lumpy. Cook for 30 seconds then slowly whisk in milk. Add nutmeg and salt; whisk until bubbly, then cook 2 minutes. Remove sauce from heat.

Spread 2 tablespoons squash puree over a lasagna noodle and sprinkle with shredded Parmesan. Roll up tightly and place into baking dish. Continue with remaining noodles. Spoon sauce over the roll-ups and top with shredded mozzarella.

Bake for 20-30 minutes or until bubbly. Serve with fresh raspberries.