Pig Nut,
Conopodium majus

This takes a little while to learn to identify but once you have tasted the sweet nuts you will learn to identify it easily. The nuts are best fresh and eaten either whilst out foraging or as soon as you get back to where you have water to wash them. It will take a little practice to perfect the art of digging them up, you will need a small trowel or a strong spoon. The tubers are about 2-6 inches below the surface. The stem usually bends slightly in which case you will not find the nut directly below the stem of the plant.