Moonfish has a special tri-colored flesh that turns white when cooked through. The flesh along the spine has an orange tone, the meat closer to the belly is a rosy-pink color and the moonfish cheeks, a less-common cut you usually have to ask for by name, has a dark red color. Moonfish collects oil in its flesh instead of its liver, so it has an oily texture best suited for steaming, grilling and roasting. Moonfish usually comes in steaks, but if you have fillets, you can use the same cooking methods but you must shorten the cooking time by a couple of minutes.
Bring a few inches of water to a boil in a pot with a steamer basket in the top. Keep the steamer basket covered until the water boils.
Season the moonfish steak or fillet to taste and place it in the steamer. Add a few lemon slices, if you like, and cover with the lid.
Steam moonfish steaks for 12 to 15 minutes; 12 minutes for steaks up to 1 inch thick and 15 minutes for those over 1 inch thick. Steam moonfish fillets for 10 to 12 minutes; 10 minutes for fillets less than 3/4 inch and 12 minutes for fillets thicker than 3/4 inch.
Heat the oven to 350 degrees Fahrenheit. Season the moonfish to taste on both sides and coat it with olive oil about 10 minutes before you want to cook it.
Place the moonfish fillets or steaks about 1 inch apart in a shallow dish and place them in the oven.
Roast moonfish fillets and steaks for 15 to 20 minutes per pound or until they feel firm to the touch; roast fillets for 15 to 17 minutes and steaks for 17 to 20 minutes.
Marinate the moonfish steaks for 15 minutes to 1 hour in your favorite marinade or a mixture of 1 tablespoon of lemon juice and 1/2 cup of olive oil for every two fillets or steaks.
Set the grill for high heat. A full tray of charcoal spread evenly in the charcoal tray brings a barbecue to high heat; set a gas grill to high heat.
Season the moonfish to taste if you didn't use a marinade and coat it with oil. Lay the moonfish on the grill.
Grill moonfish fillets or steaks for 2 minutes on each side. Turn the moonfish only once during cooking.