Preheat oven to 350 degrees. Rinse greens well; cut off any tough stems or ribs and discard. Chop greens. Heat butter or oil in large skillet. Add garlic and onion; saute 5 minutes. Add greens and cook 5 minutes longer, until wilted. Mix greens-and-onion mixture with ricotta, mozzarella, and ¼ cup Parmesan cheese in large bowl. Stir in salt and pepper.

For the sauce: Melt butter in saucepan; whisk in flour. Cook 2 minutes, whisk in rest of ingredients, and cook 5 minutes or until boiling. Remove from heat.

To assemble lasagna: Coat bottom of a large baking dish with sauce. Lay a noodle on a work surface; spread one-eighth of greens mixture evenly over it. Roll the noodle up loosely, like a jellyroll, and place seam side down in baking dish. Repeat with rest of noodles. Pour remaining sauce over noodles and sprinkle remainder of Parmesan cheese on top. Bake, uncovered, 30 minutes or until hot and bubbly.