Place halibut steaks in a shallow microwave dish, placing thickest parts towards outside edges of dish. Combine remaining ingredients in a cup and pour over the halibut steaks.

Cover dish with plastic wrap; refrigerate for 30 minutes, turning once to let marinade flavor both sides of halibut.

Turn back one corner of the plastic wrap to vent dish and microwave on HIGH power (100%) for 4 to 5 minutes. Rotate dish a quarter turn after 2 minutes.

Check fish with an instant-read thermometer to avoid overcooking. The USDA recommends a minimum temperature of 145 F.

Let stand 3 minutes before serving. If desired, garnish halibut steaks with lemon slices and parsley.