Use a knife to cut a round hole in the center of a slice of bread, about 3 inches in diameter. If you want to get really fancy, you can use the rim of a glass or cookie cutter to make a perfect shape.
Melt the butter in a non-stick skillet over medium heat. You can use a Teflon type of pan or a cast iron pan that has a good non-stick surface built up from being well seasoned. For an alternative cooking method, substitute a pie iron for the skillet and cook over a campfire.
Place the bread in the melted butter and let it lightly brown on each side, about 1-2 minutes per side. You can also do the same with the cut-out piece and use it for dipping.
Gently crack the egg and carefully pour it into the hole in the bread.
Season the egg with salt and pepper and let it cook until the egg begins to get slightly firm, about 3 minutes.
At this point the egg is almost done, but, you need to flip it over to cook the egg white. For the classic Hobo Egg, you are looking for the egg white to be fully cooked and the yolk to be runny. But, if you like your eggs firmer, just let it cook a little longer.