Cut the top quarter off each squash and reserve tops. Discard seeds. Arrange squash and place 1 of the 4 pieces of butter in each squash, cut side down, into two 11 X 7 baking dishes. Fill each dish with 1 inch of water. Preheat oven to 350 degrees. Heat a large skillet over medium high heat. Coat pan with cooking spray. Add sausage and saute 5 minutes or until browned, stirring to crumble. Remove sausage with a slotted spoon. Add spinach, tomatoes, onion and garlic to drippings in pan, then saute two minutes, stirring frequently. Stir in 1/2 cup water and bring to a boil. Combine sausage, spinach mixture, quinoa, parsley, salt and pepper, then stir in 1/2 cup cheese. Stuff about 1 cup quinoa mixture in each squash and top each serving with 1 tablespoon cheese. Arrange stuffed squashes in a broiler safe baking dish and place tops in dish. Bake for 20-30 minutes or until tender when poked with a knife. Remove from oven. Preheat broiler to high heat. Broil squashes 4 minutes or until cheese is golden.