Slice the bread horizontally (parallel with the counter) down the length of the loaf.Clean and stem the spinach. Simmer it in a closed pot with a few T of water, until limp, about 3-5 minutes. Drain and squeeze the spinach DRY, by placing in a sieve, and then pushing down on top of it with the bottom of a bowl.
2Simmer rinsed and stemmed spinach in a closed pot with a few tablespoons of water, until limp, about 3-5 minutes. Drain and squeeze the spinach DRY, by placing in a colander, and then pushing down on top of it with the bottom of a bowl. It will be HOT.
3Sauté dry spinach with garlic, salt and margarine, until just before garlic begins to brown. Add mozzarella and mix lightly until mostly melted.
4Spread the spinach mix on one side of the bread, sprinkle with half of the Parmesan. Top with the other bread, butter top of bread lightly, and then sprinkle with the rest of the Parmesan.
5Bake at 350 degrees until lightly browned, about 10-15 minutes. Slice into 1-inch slices across the loaf, so each slice has a top and bottom half. Serve hot, with ranch dressing in small bowls for individual dipping.