I had tried a recipe similar to this that I had found online.  You actually made a regular grilled cheese sandwich while cooking the burger, and then you had to open the grilled cheese to stuff in the burger.  Messy, not so great.  SO when we went camping, I came up with this much easier, much cheesier recipe!

ground beef (I usually make 1/4-pound burgers)
onion, diced
salt and pepper to taste
a variety of your favorite cheeses (we used provolone, American, and cheddar)
bread
butter or margarine
dill pickle slices

Mix ground beef with onions, salt and pepper.  Shape into patties and grill until done.  Butter 2 slices of bread per serving.  Place 1 slice of bread, butter-side down, into hot skillet, stack on cheese, burger, more cheese, pickle slices, and 2nd piece of bread, butter-side up.  Cook until bottom bread slice begins to brown.  Gently turn entire sandwich over and brown second side (cheese should be nice and melty, holding the whole yummy concoction together).