With a biscuit cutter or the rim of a glass, press a hole in the center of the slice of bread.
Heat a skillet over medium-low heat and melt in the butter. When the butter is all spread out, place the slice of bread in the skillet and crack the egg straight into the center of the hole.
Cook until the egg sets a bit on the bottom, 30 to 45 seconds. Sprinkle the egg with salt and pepper. After about a minute, flip it over with a spatula and salt and pepper the other side.
Move the toast around in the skillet, soaking up all of the glorious butter. Let it cook until the yolk feels soft. Here's the key: golden brown toast, white (not browned/burned) whites, soft unbroken yolk. Perfect.