Preheat your oven to 200°C (400°F). Using a serrated knife, cut the loaf crosswise into 8 equal slices about 1 to 1 1/2 inches thick. If you prefer the loaf connected (pull-apart style), slice the loaf nearly through leaving the bottom intact; otherwise cut fully through for individual pieces.

If you want slightly crispier interior, you can toast the cut sides under the broiler for 1–2 minutes before adding butter—watch closely to avoid burning.

Make garlic butter

Soften and mix butter

Place the softened butter (113 g) in a medium bowl. Add the minced garlic (4 cloves), chopped parsley (2 tbs), olive oil (1 tbs), salt (1 tsp), and black pepper (1/4 tsp). Mash and stir with a fork until evenly combined into a smooth spreadable garlic butter.

Stir in the grated Parmesan (2 tbs) and red pepper flakes (1/4 tsp) if using. Taste and adjust salt or garlic to preference.

Assemble and bake

Spread butter on bread

Arrange the 8 bread slices on a baking sheet, cut side up. Using a butter knife or spatula, spread about 1 to 1 1/2 tablespoons of the garlic butter on each slice, ensuring an even coat to the edges.

If using cheese, sprinkle about 2 tablespoons of shredded mozzarella over each buttered slice so it melts and browns on top.

Bake

Place the baking sheet in the preheated oven and bake for 8–10 minutes until the butter has melted and the edges of the bread are lightly golden. For a more browned, bubbly top, switch to broil for 1–2 minutes—watch closely to avoid burning.

Remove from oven and let cool 1–2 minutes.

Finish and serve

Garnish with the reserved fresh parsley (1 tbs) and serve warm. Serve as a side for pasta, soup, or as an appetizer.

Store any leftovers in an airtight container in the refrigerator for up to 2 days. Reheat in a 180°C (350°F) oven for 6–8 minutes to refresh crispness.