1Peel shrimp. Make shallow cut lengthwise down back of each shrimp; wash out vein. Press each shrimp flat into butterfly shape. Place shrimp in small glass or plastic bowl.
2In another small bowl, mix remaining ingredients except lemon; pour over shrimp. Cover; refrigerate at least 1 hour to marinate.
3Set oven control to broil. Lightly brush broiler pan rack with oil. Remove shrimp from marinade; reserve marinade. Place shrimp on rack in broiler pan.
4Broil shrimp with tops about 4 inches from heat about 5 minutes, turning and brushing once with reserved marinade, until shrimp are pink. Garnish with lemon wedges and, if desired, additional chopped fresh parsley.