Hard-boiled eggs are eggs that have been cooked in their shells in boiling water until both the white and yolk are firm. This cooking method typically takes about 9 to 12 minutes, depending on the desired firmness. Once cooked, the eggs are cooled in cold water to stop the cooking process and make peeling easier. These eggs are a popular snack and can be used in various dishes, such as salads and sandwiches. They are a good source of protein and contain essential nutrients like vitamin D and choline, making them a healthy addition to many diets.