Shape and texture matter when it comes to a perfect burger that fits on the bun. Choose a lean ground beef for your burger to avoid shrinkage and excess oil. When making your hamburger patties, use a burger press, wax paper, or a plate to flatten the patty, then create an indentation in the middle with your thumbs to retain the shape and prevent your burger from falling apart. Then, while cooking, try to resist the squish and flip. Allow the burger to cook for the full cook time and then use a large spatula to turn it over just once.