1. Cook 7 lasagna noodles according to package directions; remove with tongs or a slotted spoon to a large bowl of cold water. Repeat with remaining noodles. Drain noodles, and arrange in a single layer on clean kitchen towels. Cover with plastic wrap.
2. Cook onion in hot oil in a saucepan over medium heat, stirring occasionally, 8 minutes or until onion is caramel colored. Add garlic, and sauté 1 minute. Reserve 1/4 cup onion mixture. Whisk flour into remaining onion mixture in saucepan, and cook, whisking constantly, 1 minute. Gradually whisk in milk. Cook over medium heat, whisking constantly, 8 to 10 minutes or until sauce is thickened and bubbly. Remove from heat; stir in 3/4 tsp. salt, 1/4 tsp. pepper, and 1/8 tsp. nutmeg. Spoon 1/2 cup sauce into a lightly greased 13- x 9-inch baking dish.
3. Drain spinach well, pressing between paper towels.
4. Preheat oven to 425°. Stir together spinach, cottage cheese, mozzarella cheese, egg, reserved 1/4 cup onion mixture, and remaining 1 tsp. salt and 1/4 tsp. pepper.
5. Spread about 3 Tbsp. spinach mixture over 1 noodle; roll up firmly, and place, seam side down, in prepared baking dish. Repeat with remaining noodles and spinach mixture. Spoon remaining sauce over rollups, and sprinkle with Parmesan cheese.
6. Bake at 425° for 20 to 25 minutes or until golden and bubbly. Let stand 5 minutes before serving.