Preheat oven to 350°F.
Stir together the butter, oil, garlic and parsley in a small bowl.
Using a serrated knife cut the bread into 1-inch-thick slices without cutting all the way through to the bottom, leave the slices attached to each other.
Gently pull apart the slices and use a pastry brush to butter them with the garlic mixture.
Wrap the loaf in foil and bake in the center of the oven for 15 minutes. Remove from the oven, unwrap and let cool until you can handle it without being burned.
Heat the broiler with the oven rack in the center.
Cut the slices all the way through and lay them out on baking sheets. Mix the parmesan, cheddar and mozzarella together.
Top each slice with cheese and a sprinkle of Italian seasoning.
Broil them with the oven door ajar until bubbly with some golden spots about 3 minutes - check them often. Serve warm.
Reheat leftovers in the oven about 5 minutes on 350 degrees F.