Heat pan over medium heat. When hot, add your choice of fat. I prefer to use a neutral vegetable oil, although I will sometimes use ½ tablespoon of oil, let it heat, and then add ½ tablespoon of butter and heat until just foaming.
Tilt the pan to evenly distribute the fat and carefully crack your egg just over the surface of the pan.
Let cook for one minute on medium heat. You can season the egg now or wait until done. It doesn't make a difference.
Cover the pan and cook for one more minute. If your pan does not have a lid, use a small sheet pan, or aluminum foil, to cover the pan completely.
After one minute covered, your sunny side up egg should be done. If you want the whites cooked more, add 1 teaspoon of water and cover again for about 30 seconds.
For over easy or over medium eggs, use a flexible spatula and gently flip over your egg. See below for specific cook times for each egg.
Sunny side up: After one minute uncovered, cook for one minute to 90 seconds covered, or until whites are completely set and the yolk is still runny.
Over-easy: Use a spatula to carefully flip your egg onto the second side and cook for only about 10 to 15 seconds, or until the whites covering the yolk are cooked, but the yolk is still runny.
Over-medium: Use a spatula to carefully flip your egg onto the second side and cook for another minute to 90 seconds, so the yolk is jammy and barely runny. Cook 2 minutes if you want your yolk fully cooked.
Transfer to a plate, season to taste, and serve immediately.