Preheat your oven to 375°F (190°C). Arrange the bread slices on a baking sheet, ensuring they are spaced apart evenly.
In a small bowl, combine the melted butter with the finely minced garlic and a pinch of salt if desired. Mix well until the garlic is evenly dispersed.
Spread the garlic butter generously over each bread slice using a brush or spoon, ensuring coverage from edge to edge.
Sprinkle shredded mozzarella evenly over the coated bread slices, followed by grated Parmesan cheese for extra flavor.
Bake in the preheated oven for 12-15 minutes, or until the cheese is melted and bubbly, and the edges of the bread are golden brown. You should hear a slight bubbling and see crispy edges.
Remove from oven and garnish with chopped fresh parsley if desired. Serve warm, with the cheese and garlic aroma filling the air.