Perfect soft-boiled eggs:
Put the eggs into a bowl of warm tap water for at least 15 minutes, so that they will be warm and not crack and leak from too rapid a temperature change when they hit the boiling water. If you try to start cold eggs out in cold water and bring them slowly to a boil, it’s too hard to judge just when to start timing them. The pre-warming eliminates this ambiguity.
Meanwhile, bring a pot of water to a full rolling boil. Put the pre-warmed eggs into it and instantly set your timer: 3.5 minutes for large eggs, 4 minutes for jumbos. This assumes you like just-set whites and runny yolks, like me. Serve 'em up with hot buttered toast.