Set an oven rack about 6 inches from the heat source and preheat the oven's broiler. Lightly grease a baking pan.
Combine butter, garlic, soy sauce, parsley, and pepper in a microwave-safe bowl. Microwave on high until butter is melted, stirring halfway through, about 2 minutes.
Arrange chicken, skin-side up, on the prepared baking pan. Pour most of the butter mixture over top to coat, reserving some for basting.
Broil in the preheated oven until no longer pink in the center and the juices run clear, turning and basting occasionally, about 20 minutes. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C). Garnish with parsley to serve.