I season the meat with a little garlic salt and some Steakhouse seasoning and a tad of lea and perrins worcestershire sauce. Then i cook up some bacon to a barely crunchy texture and crumble it in a bowl. Then i take about a 1/3 lb patty and sorta make a bowl with it, square is helpful and put some of the bacon inside along with your favorite cheese. Cheddar is a good one but Pepper jack is also good. then use those four flaps and close up the burger.
Viola Bacon and cheese stuffed Burgers. Prepare your tongue for orgasms.
Onion and mushrooms would also rock, perhaps a little Jalapeno tossed in or something.
Just cook it more than these assholes do, Pink ground beef is not good to eat, ever.