Hazelnuts are small, round nuts that grow on the hazel tree. They have a hard outer shell that encases a smooth, creamy nut inside. Hazelnuts have a rich, slightly sweet flavor with a hint of bitterness, making them a versatile ingredient in both sweet and savory dishes. They are commonly used in baking, confectionery, and as a key ingredient in popular spreads like Nutella. Hazelnuts are also a good source of healthy fats, protein, and various vitamins and minerals, making them a nutritious addition to your diet.