If your kids want burgers for dinner, and you know you won't have the time to both prep and grill them when you get home in the evening, look to your trusty slow cooker to lend you a hand. Slow cookers are not just for stews or chili; you can prepare steak, chicken and even burgers in a slow cooker. All you have to do is prepare the patties in the morning, throw them in the slow cooker with a simple sauce to prevent burning, and come home to fully cooked patties, ready to serve in the evening.
Place the chopped onion into the slow cooker. Combine the ground beef and 1 egg in a bowl. Mix them well and season them with salt and pepper. Add additional spices as you see fit.
Shape the beef mixture into six evenly sized hamburger patties, about 3/4-inch thick. Place the individual patties stacked on top of each other, in the slow cooker on top of the onions. If the crock pot is large enough, you may be able to make two stacks of three patties.
Pour favorite barbecue sauce, whether store bought or homemade, on top of the patties. This allows the patties to simmer in a sauce, which is necessary when cooking in a slow cooker. Alternately you can use other types of sauce such as a ketchup mix or a cream of mushroom soup, depending on what you want your burgers to taste like.
Cover the slow cooker with the lid and set the heat to low. Leave the patties to cook for seven to nine hours, until the meat is soft and tender, and the juices run clear. Separate the patties with a spatula before serving.