Hard-boiling eggs is actually a misnomer because the eggs are not boiled at all. Rather, they are cooked in water that comes to a boil and then sits covered at the nearly boiling temperature until the eggs are hard-set.
Time-Frame
Place room temperature large eggs in one layer in a pot or saucepan and add enough cold water to cover them with about one inch of water. Bring the water to a boil, and as soon as it boils, remove the pan from the heat, cover it, and wait 15 minutes until the eggs are hard-cooked. Hold the eggs under cold running water to stop them from cooking more.
Considerations
The timing changes slightly when eggs are a different size or start refrigerated. Small and medium eggs should only sit in the hot water for 12 minutes after it boils, and extra large or jumbo eggs need 18 minutes. Add two minutes to any of these times if the eggs came directly from the refrigerator instead of being at room temperature.
Expert Insight
According to Joy of Cooking, fresher eggs are much more difficult to peel after being hard-cooked than old eggs. For best results, wait seven to 10 days after purchasing eggs before cooking them.
Tags: room temperature, until eggs