Mix together all ingredients except meat. Combine with the meat and mix well. Cut two large sheets of waxed or parchment paper.
Roll meat mixture into a 18" X 8" rectangle and remove top layer of paper. Leaving a 1" border on all sides, spread a layer of spinach over meat, and followed by cheese mixture and 1 cup of sauce.
Roll meat from the short end, just like you would when making a jellyroll cake, lifting the paper out of the way as you go. Don't worry if some of the filling oozes out, just tuck it back in.
Carefully transfer roll, seam side up, to a 9" X 5" loaf pan. Bake for about 1 hour and 10 minutes or until temperature on a meat thermometer reaches 145° F.
Let stand for 20 minutes before removing from pan. Drain off excess fat, remove from pan. Serve in slices, covered in the remaining tomato sauce.