The best way to cook waterfowl breasts. Marinade them in a bowl or plastic bag for at least 8 hours in the refrigerator. Cook on the grill like you would a steak to medium rare. The marinade is - 1/4 cup olive oil or vegetable oil, 1/4 cup soy sauce, 2 tbsp. ketchup, 1 tbsp. vinegar, 1/4...