In a large bowl, mix the butter, soy sauce, garlic and pepper. Reserve 1/4 cup soy mixture for basting. Add chicken to remaining soy mixture; turn to coat.
Place chicken on a broiler pan, skin side down. Broil 4-6 in. from the heat for 10-15 minutes on each side or until a thermometer reads 170°-175°. Brush occasionally with reserved soy mixture during the last 10 minutes of cooking.