Heat a frying pan to medium heat. Add a generous amount of butter, and allow it to melt. Meanwhile, use a glass to cut a round hole in the slice of bread and remove the inner bit.
Once the butter is melted, add bread to the pan. Fry it on one side first and then turn it around, adding some more butter in the process. (The aim is to not burn the bread and get plenty of butter into it) Just put a lump of butter into the bread slice’s hole, making it easy to move the liquid butter right into the bread.
Once the bread is turned over add the egg into the hole and fry it there. Because of the low heat this takes a while, particularly as the egg will be a bit thicker than your standard fried egg. You do need to turn the egg just like any other fried egg. In fact the turning over process has never been as easy as in this case because the bread gives extra stability to the whole thing. Add salt and pepper to taste.