Mash butter, garlic, pepper and lemon juice together in small bowl. Butter should be of uniform texture and slightly coarse. Don not over mix to completely smooth texture or it will take too long to firm up.
Place softened butter on a piece of plastic wrap and form into log, using plastic to form casing. Place butter in freezer to firm up until just before serving the meal. Butter will firm up faster if you place it directly on the freezer shelf.
At last minute, remove plastic wrap and slice log into 8 pieces.
Coat chicken with olive oil, salt and pepper in bowl.
Grill, broil or pan-grill chicken 4 to 6 minutes on each side.
Top with 1 to 2 slices of garlic butter. Serve immediately.