At a Shabbat lunch in Madrid not long ago, the conversation turned to the question of boiling eggs. One of the guests mentioned that a Dutch rabbi he knew had heard that in order to make it more likely that boiled eggs be kosher, you should add an egg to the pot if the number you began with was even. According to the laws of Kashruth, Jews may not consume eggs containing blood spots. When observant Jews make an omelet or bake challah, they break each egg separately and discard any that are bloody before they add them to the rest of the ingredients. But when you boil eggs, there is no easy way to tell beforehand if the eggs you are cooking have blood spots or not. Once the eggs are boiled and opened, the spots can be seen, but by then it is too late. All the eggs must be discarded, and a pot in which bloodied eggs are cooked is no longer kosher.