The 5-5-5 method refers to cooking eggs in a pressure cooker for 5 minutes, letting the pressure release naturally for 5 minutes, and then placing the eggs in ice water for 5 minutes. This method is known for producing perfectly cooked hard boiled eggs. If you ever pressure cook 555 eggs and you get a gray ring around the egg yolk, you can also try the 6-1-5 method too! Pressure cook for 6 minutes, do a natural release for 1 minute, and then put the eggs in a water bath for 5+ minutes until they're cool.