Beef soup bones are typically dense bones from the leg or knuckle of cattle, often containing marrow and connective tissue. When simmered slowly in water, these bones release their collagen, minerals, and rich flavor, creating a nutrient-dense broth. The marrow inside the bones adds a velvety texture and deep flavor to soups and stews, while the gelatin from the connective tissues helps give the broth body. They are a traditional ingredient used to make both light and hearty broths, prized for their ability to enhance the depth and complexity of a dish.