Steam, don’t boil! The shell almost always peels right off, often in one piece. No green line.
In a steamer basket in a saucepan, place eggs in a single layer. Fill pan with water to just below the steamer holes.
Heat over medium-high heat until water begins to bubble, and then cover tightly. Steam for 15 minutes. Remove from heat, drain, and run cool water over. Let sit in cool water for about 15 minutes, or until you can handle the eggs. Crack shell on counter and peel.