Arrange bread slices in 1 layer on a large baking sheet and brush tops with 3 tablespoons of oil.
Stir together remaining tablespoon of oil, cheese, garlic, 1/4 teaspoon of kosher salt, and 1/4 teaspoon pepper in a small bowl. Sprinkle each slice of bread with about 1 teaspoon of cheese mixture, mounding it slightly.
Bake until topping begins to melt, about 6-8 minutes. Sprinkle with parsley and kosher salt to taste. Serve warm. Makes 24 appetizers.