Castilian Lentils from Salamanca The Castilian lentil is the largest of all lentils, measuring between 7 and 9 millimeters, and are light green with some darker grains, known as "avinatadas lentils". The color of the Castilian lentil darkens over time. Its grain is wide, rounded, flattened, and lentil-shaped. These dry legumes have very thin skin and stand out for their tenderness and mild flavor. The Castilian lentil cooks excellently in any type of water.