Mustard greens are leafy vegetables that belong to the Brassicaceae family, which includes cabbage, broccoli, and kale. These greens are known for their peppery and slightly bitter flavor, which varies depending on the variety and maturity of the leaves. Mustard greens come in different shapes and sizes, but they typically have dark green leaves with a textured surface. They are widely used in various cuisines around the world and are appreciated for their nutritional value and distinctive taste.