Soft boiled eggs are cooked for 2-3 minutes and medium boiled for 5-6 minutes. I learned from Raymond Blanc that the secret is to cook them so that the water is barely at a tremor. I subsequently add a minute to the time. By cooking them in this way there is an equality of texture throughout the egg. For hard boiled eggs, I put them in cold water and time the entire process for 15 minutes, heating the water slowly to a boil and then lowering the heat.