Mix the ground beef with some dehydrated onions, then form the patties. They should be just slightly bigger than the bun.
Put some water in the bottom of a pot and place a steamer basket inside. Lay some onions on the bottom, then top them with the burgers. Cover the pot and steam for about 5 to 8 ten minutes.
Top each burger with thick slices of cheddar, cover the pan and steam again for about 30 seconds - long enough for the cheese to melt.
Remove the onion and chop it. Put it on top of the cheese.