A sunny-side-up egg cooked uncovered over medium-low heat takes about 2-3 minutes for a runny yolk; covering the pan traps steam that gently sets the top of the yolk too, pushing the time to 3-4 minutes. For a fully set yolk, plan on 5-6 minutes.
Why Does the Heat Setting Matter So Much?
On high heat the white puffs up and hardens fast, the edges start to brown while the yolk is still cold underneath — which is why medium-low is the setting to use. Lower heat takes longer overall, but the white cooks evenly all the way through and the yolk stays exactly where you want it.
Lid On or Lid Off?
Cooked uncovered, the top of the yolk stays raw, which is what people who like a very runny yolk are after. Covering the pan traps steam that lightly sets the surface of the yolk while keeping the inside runny — that middle ground takes about 3-4 minutes. For a fully set yolk, keep the lid on the whole time and give it 5-6 minutes.
One Egg or Two?
Two eggs cracked into the pan at once take slightly longer than one, because the extra volume of egg white briefly cools the pan down. The difference is usually only thirty seconds to a minute, though pan size and whether the eggs touch each other also play a part.
Butter or Oil?
Eggs fried in butter need a lower heat, since butter starts to burn at a lower temperature than most cooking oils, and burnt butter turns bitter. Oil tolerates higher heat and cooks a touch faster, but it will not give you the same richness or flavour that butter does.
Common Mistakes
The most common mistake is cracking the egg into a pan that is not hot enough yet, which lets the white spread out thin and shapeless. The second is turning up the heat to save time — the edges burn while the yolk is still cold. Medium-low heat and a little patience keep both the shape and the doneness right where you want them.
When Should You Add Salt?
Salt is best sprinkled on the yolk after it is cooked, not during — salting the yolk early can break its texture and leave it speckled. A little salt on the white early on actually helps it cook faster, since salt slightly lowers the temperature at which egg white sets.
How Do You Get Crispy, Lacy Edges?
For a lacy, bubbly edge, turn the heat up a touch and add a few extra drops of oil right before cracking the egg in; when the oil is hot the edges of the white puff up and crisp within 1 minute. After that, drop the heat back down and let the yolk finish cooking at its normal pace.
Not the Same as Poached or Boiled
A sunny-side-up egg uses a different technique and a different timeframe than a poached or boiled egg; a poached egg sets faster in simmering water, while a fried egg's timing depends on pan heat and whether the lid is on. Mixing up the two methods and applying the same timing to both leaves you with either a raw egg or an overcooked one.