Position an oven rack about 4–6 inches below the broiler element and preheat the oven to the broil setting.
In a large bowl, combine ½ cup (1 stick) butter (room temperature), ¼ cup grated Parmesan cheese, 2 cloves garlic (minced), and 1¼ teaspoons Italian seasoning. Add ground black pepper to taste.
Stir the mixture until it is well combined and spreadable.
Slice the Italian bread loaf in half lengthwise so you have two long cut surfaces.
Spread the garlic butter mixture evenly and generously over the cut sides of both bread halves.
Place the bread cut-side up on a baking sheet and broil until the tops are golden brown to your liking, about 1–3 minutes—watch very closely so it does not burn.
Remove from the oven, let cool briefly, slice, and serve.