We tried Tabasco, and mustard, but our hen also loved it, the only thing which stopped her was when we started collecting the eggs more often, and not leaving them in the nestbox so long. Egg eating starts usually when an egg gets broken, and they have a peck at the contents, the more often you can collect them, the less chance they have of standing on them and breaking them. The cloth over the nestbox works too, as they have really bad eye sight in the dark, so less chance of seeing the eggs already laid. It becomes a habit in a very short space of time, and a very hard one to stop.
JubesX