Cut fillet in 4 serving pieces. Place large side of fillet toward edge of pyrex baking dish with center open. Pierce fish, dot fish with butter, and cover with plastic wrap. Microwave Medium (50%) for 5 minutes. Mix mayonaise, parsley, onion, and dill togerther. Spread mayonnaise mixture on top of fillets and microwave Medium (50%) covered for 5-6 minutes before serving. Garnish with lemon wedges. If steaks are used, arrange with thin ends toward center of dish. One inch steaks should be microwaved 5 minutes a medium power, covered with mayonnaise mixture and microwaved for 5-6 minutes longer.