Preheat oven to 350 degrees F. (Bread can also be done on the grill or in a barbeque pit.)
Combine the butter, garlic, lemon juice, parsley, and black pepper in a small mixing bowl. Stir to blend well. Spread both halves of the bread with the mixture. Put the halves together, wrap in a sheet of aluminum foil, and place in the oven or on the grill until bread is heated through, about 15 minutes. Serve warm.
Reserve leftover bread for croutons.