Preheat a grill to high heat. Combine the olive oil, garlic, basil, parsley, rosemary, salt and pepper in a small bowl and allow to sit 10 to 15 minutes, covered, at room temperature.
Cut the bread slices diagonally. Lightly brush 1 side of the bread triangles with the oil mix and place oiled-side up on the grill. Grill 2 to 3 minutes, flip and cook until nicely marked, 1 to 2 minutes more. Remove, dice into 3/4-inch cubes with a serrated knife and serve hot.
Cook's Note: Can be premade and quickly reheated in a broiler for 45 seconds to 1 minute.
Recipe courtesy of Guy Fieri