The American Egg Board recommends the following method for making hard-boiled eggs:
“Place eggs in single layer in saucepan. Add enough tap water to come at least 1 inch above eggs. Cover. Quickly bring just to boiling. Turn off heat. If necessary, remove pan from burner to prevent further boiling. Let eggs stand, covered, in the hot water about 15 minutes for Large eggs (12 minutes for Medium, 18 for Extra Large).”
But take it with a grain of salt. As the nation’s self-proclaimed eggsperts, the AEB must disseminate instructions that will work for the average cook. But one can drown in water that averages only six inches in depth.
Eggs may vary not only in size and freshness but also in their temperatures when placed in the saucepan, so they may not all reach boiling temperature as soon as the water boils. Also, different stoves and different pans will require different amounts of time to boil the water. And after the burner is turned off a heavy, porcelain lined iron saucepan will keep its water hot longer and at a higher temperature than a thin aluminum one.
For these reasons, we have not found the AEB’s recommendations to be reliable. So what do we advise? Follow the AEB’s instructions up until the water boils. But don’t turn off the heat; turn it down to a bare simmer and begin your timing.
Using the AEB values as a guide, base your timing on your own experience with your own stove and saucepan, your own usual-sized eggs, your own refrigerator, and the degree of hardness you prefer in your yolks.
It’s worth sacrificing a few eggs to the gods of experimentation to find your “personal best.” Jot down your chosen simmering time on a piece of paper and tape it to the inside of a kitchen cabinet door.