Place fillets on a piece of tin foil. Place the onions, line and garlic on top of the fillets. Season with salt and pepper and sprinkle some capers on top. Add a little butter and oil. Close foil, making a tent, then put on the grill. Grill for 10 to 15 minutes, until just opaque and tender.
A viewer or guest of the show, who may not be a professional cook, provided this recipe. It has not been tested for home use.