I've often struggled to perfect soft-boiled eggs, so I embarked on a series of rigorous scientific experiments to devise a foolproof method. Here's the fruit of my labours. It's based on putting the eggs into cold water, not boiling.
Pierce a tiny hole in the egg using an egg pricker or piercer. This step helps prevent the egg from cracking during boiling.
Place the egg in a saucepan and cover it with cold water. Add a pinch of salt. The salt increases the boiling point of water slightly, which can help the egg cook evenly.
Heat the water until it reaches a gentle boil – look for just a few bubbles, not a vigorous boil.
Once the water starts bubbling gently, begin timing. For a soft-boiled egg with a runny yolk, cook for between 1 minute 50 seconds and 2 minutes.
Remove the egg from the water and let it sit for a minute or two. This brief resting period allows the egg to finish cooking gently in its residual heat.
Enjoy your perfectly soft-boiled egg with soldiers or however you prefer.
Notes
If the eggs are not at room temperature, they will need to be boiled for longer, probably at least 30 seconds more.