Egg yolk is the rich, golden-center of an egg, which is suspended in the egg white by a filament called the chalaza. This vibrant-yellow part of the egg is encapsulated within a protective, clear casing known as the vitelline membrane.

This creamy center comprises approximately 33% of an egg’s liquid content and is packed with nutrients. In comparison to the egg white, the yolk is richer in calories and contains more fat, cholesterol, and essential vitamins like A, D, E, and K. It is also abundant in critical nutrients like choline and selenium.

Egg yolks bring a lot more to the table than just nutrition. In cooking and baking, they play an integral part in binding ingredients, emulsifying sauces, leavening baked goods, and imparting a rich flavor and color to various dishes. Their high-fat content adds a creamy, smooth texture that enriches sauces, custards, ice creams, and mayonnaise.

When heated, egg yolks can add a distinctive thickening property to dishes. In baking, they play a crucial role in providing moisture to the batter, leading to a tender, soft crumb in cakes and bread.

Lastly, it’s crucial to mention the color contribution of the egg yolk. While the taste they add to dishes is subtle, the vibrant, sunny yellow can make a dish visually more appetizing and appealing.

Egg yolks are typically not sold separately in grocery stores. They are found inside whole eggs, which you can find in the dairy or refrigerated section of a grocery store. However, some stores might carry cartons of egg yolks or liquid egg product which can also be found in the refrigerated section with other egg products. You may also find powdered egg yolks in the baking aisle.