1Slice the bread down the LENGTH of the loaf, but don't sever it.
2Clean and stem spinach. Simmer in a covered pot with a few tablespoons of water just until limp, about 3-5 minutes. Drain and squeeze it DRY, by placing in a colander, and pressing on it with the bottom of a bowl or plate.
3Saute spinach with garlic, salt and butter, until garlic just begins to brown, about two minutes. Add mozzarella and mix lightly.
4Spread spinach mix on one side of the bread, and sprinkle with most of the Parmesan. Close the loaf, butter the top crust lightly, and sprinkle with the rest of the Parmesan.
5Bake at 350 degrees until lightly browned, about 10-15 minutes. Serve hot, in 1-inch slices, with Ranch dressing on the side for dipping.