This is so easy plus you get to throw away the vessel you cooked it in. You can cook them in the oven, on the BBQ or on hot coals of a camp fire. I usually go for the BBQ. It is a complete dinner in a packet.
Mix hamburger, salt, pepper and garlic powder to taste and make 4 patties. Put them on the foil in the center.
Put sliced onions next then the carrots and potatoes on top of the onion. Just kind of eyeball them and make each packet even with the slices on top. You can add a little more salt and pepper. If you like you can also put some green bean on top of the other ingredients. Add one tablespoon of stock or water to each packet.
fold the long side of the foil to the center and just keep folding until it is tight. Then roll up the ends towards the center until you have a nice packet. Bake at 350 in the oven for about an hour or on the BBQ grill at medium heat for about 30 minutes. If your burgers are too thick it might take 15 minutes longer. I use the non stick foil which is a little stronger.