Egg yolks are the yellow part of an egg, found at the center of the egg white. They are rich in nutrients, including vitamins A, D, E, and K, as well as essential fatty acids and proteins. Egg yolks play a crucial role in the development of a chick, providing the necessary nutrients for growth. In cooking, egg yolks are often used to add richness and flavor to dishes. They are key ingredients in many recipes, such as mayonnaise, custards, and sauces. Additionally, egg yolks can be used as a natural emulsifier, helping to blend ingredients that typically do not mix well.