When I was a young man, nearly 50 years ago, I worked as a trainee with a cook who did something somewhat similar. He would cook one side of the eggs in a small

When I was a young man, nearly 50 years ago, I worked as a trainee with a cook who did something somewhat similar. He would cook one side of the eggs in a small egg pan, and then slide them onto a large dark leaf of lettuce (romaine?) placed on the grill (a flat smooth affair, not a grate). The egg and the lettuce were then covered with a cheap pie tin -- the type one gets when buying a pie to take home from the restaurant. I suspect the goal was to stop the bottom from over cooking (insulate it) and perhaps generate a bit of steam to help with setting the top of the eggs slightly. The goal was perfect sunny-side up eggs as best I recall. Seems like it would work just as well with all steps done in a cast iron pan?