Place your egg in a small pot and cover with cold water. The water should be about an inch or so higher than the egg. Cover the pot with a lid. Over high heat, bring your eggs to a rolling boil.
Remove from heat and let stand, 18 minutes for medium sized eggs, 20 minutes for large eggs and 23 minutes for extra large eggs.
Drain water and immediately run cold water over eggs until cooled. Rapid cooling helps prevent a green ring from forming around the yolks.
Peel eggs and place in a bowl. Mash well and set aside.
Cut avocado in half, remove pit and scoop out flesh. Place avocado flesh in a bowl and mash well with a fork. Combine egg and avocado together and mash together well until you have your desired consistency.