This is a quick and delicious accompaniment to a spaghetti dinner.
Preheat oven to 350 degrees. Make garlic paste: Coarsely chop garlic, and gather into a pile. Sprinkle generously with coarse salt. Place flat side of knife blade on top of garlic, with sharp side of blade away from you; press down firmly while pulling knife toward you. Repeat until a paste forms.
Combine garlic paste, butter, and 1/8 teaspoon each salt and pepper in a small bowl. Brush butter mixture on cut sides of bread; sandwich together. Place on a baking sheet, and bake until heated through and crispy, about 12 minutes. Slice and serve.