How to prevent the ugly green layer on the yolk. Cover the eggs in a pot with water:

1. Heat the pot on high heat and bring the water to a full rolling boil.

2. Turn off the heat, keep the pan on the hot burner, covered, and let sit for 10-12 minutes.

3.  Strain the water from the pan and run cold water over the eggs to cool them quickly and stop them from cooking further. Over cooking causes the green stuff on yolk.