When the feta ring is sizzling and the underside is clearly browning, carefully crack the egg into the open center. If needed, tilt the pan slightly so the white stays mostly in the middle and doesn’t completely cover the cheese.
Continue cooking over medium heat for 3 to 4 minutes, or until the egg white is fully set but the yolk is still runny, and the feta has a dark golden, crispy edge. If the cheese threatens to burn before the white sets, briefly lower the heat.
