There is really no trick to it, so if you own an electric stove this is the end all be all guide to soft boiling an egg.
Pour 4 tablespoons of water in a small pot and put the egg in. With the lid on, heat on maximum setting until you can see steam exiting from under the lid. Immidiately turn off the heat entirely and start the egg timer on four minutes.
When the four minutes are up your egg is done and ready to eat, though be warned it is quite hot at this time, so you might want to wait a minute or two. Of course depending on the size of the egg and your particular taste, you might want to extend the cooking time by thirty seconds or maybe even a minute. Also if you need your egg to be hard boiled instead, simply extend the cooking time to around eight to nine minutes.
You can boil more than one egg at a time using this method, actually as many as will fit inside the pot without stacking them. I have not tried stacking the eggs so I really don't know if it would work, but since the cooking method depend on steam surrounding the egg, I think it would be bad. Use the same amount of water and the same cooking time.
How it works
This method of boiling an egg might sound novel to some. The canonical boiling rules for eggs after all dictate, that you should cover the egg entirely by water. However on an electric stove this is a bad idea for a couple of reasons.
First of all common physics teaches us that the amount of energy it takes to heat a volume of water one degree is directly proportional to the volume or mass of water. Now filling the pot with water so it just covers the egg will take approximately 0.6 liters of water. On the other hand, four tablespoons of water amounts to just 0.06 liters of water or less. It is now a mater of simple math to calculate that the amount of energy required to bring the water to boiling point is ten times as high with the egg covered by water as opposed to when you just use the four tablespoons worth.
The second reason is slightly more subtle. In both cases when the water boils the stoves work is done, in principle. You turn it off. If you covered the egg with water it also means that you egg is done and ready to eat. However if you use the electricity saving method described above, this is where the real boiling time starts. At this point the pot is entirely filled with hot steam, but not all the water has evaporated from the bottom yet. When you turn off the heat at this point the bottom of the pot and the cooking plate will remain very hot for quite a while. All that heat just goes wasted using conventional cooking techniques, but with this method we use the remaining heat to make sure, that the egg is enclosed in hot steam for the remainder of the boiling period.
The end result is that you use considerably less energy to boil your egg. You can also use this method on advanced electric stoves like ceramic and induction stoves, but you might have to extend the cooking time a bit, because these kinds of stoves does not generate quite as much residual heat.
Ending notes
- But you cannot possibly steam boil an egg?!
To quote my university physics professor Jens Martin Knudsen - "The experiment decides the case."
In other words, try it. See what you think. I have tried it myself plenty of times.
And one last thing. My mom would suggest serving your soft boiled egg with two slices of home made rye bread with butter and salt between. You can also add salt to the egg while eating it if you feel the need. Fresh orange juice goes nicely with soft boiled eggs.