Thaw rolls until warm and bubbly; knead into a ball. Roll into a 12x18 inch rectangle. Fry sausage with onion until done. Spread with spaghetti sauce. Thaw spinach and squeeze out all excess liquid between two paper towels. Spread spinach over dough. Sprinkle with sausage and Mozzarella cheese. Fold one-third of rectangle to middle. Repeat with other side. Tuck under ends and place on greased cookie sheet. Vent top with scissor "V" cuts down middle. Bake at 350 degrees for 20 to 25 minutes.
Variation: Omit spinach and onions, use plain sausage.
