Prepare pasta according to directions.
Drain and set aside.
Preheat oven to 350 degrees.
Lightly grease a 13- x 9-inch baking dish.
Heat butter in a Dutch oven over medium-high heat; saute onion 5 minutes or until just brown.
Add garlic, and cook about 1 minute.
Reduce heat to medium-low, and add greens; cover and cook 15 to 20 minutes or until greens are tender, stirring occasionally.
Sprinkle greens with flour.
Cook uncovered, stirring constantly, 1 minute.
Gradually add milk, stirring well.
Cook 5 minutes, stirring often, until thickened and smooth.
Remove from heat; stir in cooked pasta, mozzarella, and next 5 ingredients.
Place into prepared dish, and sprinkle evenly with Parmesan.
Bake at 350 degrees for 15 to 20 minutes.
Prep: 10 minutes Cook: 30 minutes Bake: 15 minutes.