Take the guesswork out of hard-boiled eggs.

This is the secret to perfectly boiled eggs. Simply pop it in the pan with your eggs and as your eggs boil, the egg-shaped timer reacts to the heat, changing color to show how well done the eggs are.

Whether it’s the classy poach, the humble boil, the decadent fry, or the versatile omelette, egg cookery is an essential technique in the pantheon of kitchen standards. There are books and blogs ...