Crunchy tubers that produce are product of a sedge. Soak the nuts for 24 hours before planting out at the end of May. Keep them weeded and wet and harvest them around the frost by sifting them out of the soil, then blasting them with water until they are clean. Dry, and then you can snack on them or make Horchata de Chufa (a Spanish drink)!
This variety is my personal favourite, I find the nuts softer and sweeter than most other varieties.