Cooking on a George Foreman grill has a number of advantages, including allowing indoor grilling and eliminating of a good portion of the fat from the meat you are grilling. Another main reason why many people cook on a George Foreman grill is that you can put frozen foods, such as hamburgers, directly onto the grill and the food will still cook thoroughly, as the grill heats the food from both sides.
Preheat the grill by plugging it in. Most George Foreman grills simply have one setting, and after you plug in the grill, the preheat light will go off when the grill is preheated. Some George Foreman grills have an on/off switch, so make sure that is in the "on" position if present. Preheating the grill normally takes around 5 minutes.
Place the burgers flat on the grill, so that the entire patty is touching the bottom grill plate, making sure that no part of the burgers are hanging off. Season the patties if you choose, and then close the grill. Make sure the top grill plate is in contact with all of the patties. The patties can be very close to each other when you start, as they will shrink while cooking.
Cook the burgers for about 5 to 7 minutes, checking periodically for doneness. With a George Foreman grill, you can simply lift the lid and check the burgers without compromising the heat or cooking time of the patties. When cooking from frozen, cooking times can vary depending on the thickness of the burgers.
Use a spatula to take the burgers off the grill when they are done. Since the grill plates cook the burgers on both sides, there is no need to flip the burgers, but you can open the top lid to season the patties or add cheese if you desire.