Hard boiling is a type of cooking method for whole eggs. They are submerged in boiling water to cook through the whites and yolks, then the shells are peeled away before serving. Hard-boiled eggs are often served as an appetizer or salad topping. Although they tend to be best served fresh, you don't have to waste the leftovers. Hard-boiled eggs can be frozen and thawed for another time, but not all parts of the egg can withstand the freezing process and remain edible.
Slice your hard-boiled eggs in half lengthwise and scoop out the bright yellow yolks. Discard any leftover hard-boiled egg whites--they will become tough and leak water if they are frozen and thawed, making them unpleasant in both taste and appearance. Transfer the egg yolks into an airtight container. Arrange the yolks carefully in a single, even layer and seal the container tightly to prevent any air from reaching the insides and disturbing the freezing process. Label the contents and the date with a black marker so you can remember how long the yolks have been stored and use them before they are past their prime. Add the container to your freezer--the frozen hard egg yolks will keep in there for up to one year, according to the American Egg Board. Remove the frozen hard egg yolk container from your freezer when you're ready to use them. Store the container in the refrigerator until the yolks completely defrost, approximately 30 minutes or so. Use the yolks as soon as they are thawed for the best results. Crumble or chop the yolks into pieces and serve as a topping or garnish for salads or other dishes.
Save room in your freezer by adding the hard-cooked egg yolks to a plastic storage bag instead of an airtight container and lay the bag flat across a freezer shelf.
Add crumbled hard-cooked egg yolks to cooked vegetables, such as spinach, to increase the dish's protein factor and give it a new flavor.