Delia Smith's How To Cheat at Cooking -- sorry to bang on about it again -- is not just about throwing together tins of this and frozen packets of that. It offers some cooking instructions too. One that interested me was her recipe for poached eggs: you slip the eggs into the simmering water, cook them for a minute, then turn off the heat and cover the pan, waiting for a further six minutes.
The theory behind this technique is that the egg whites, like any protein, will toughen if cooked too aggressively. Salt and vinegar in the water also help to keep them tender; unfortunately, they also prevent the egg cohering. As I have note in the comments section of this entry, I now poach eggs in water with nothing added.
I crack the eggs into cups before slipping them into the water, because I am likely to make a mess of them if I try to perform the operation in one go. If there are more than two, they will lower the temperature of the water considerably, so I keep the heat high; if there are four eggs, the water may just be returning to simmering point by the time the first minute is up.
I like poached eggs to be well done, but still squidgy. A further six minutes in the water is too long even for large eggs, I have found. Four and a half to five minutes is about right. I lift them out of the water with a slotted spoon, holding a paper towel held underneath.