Put the pork in a bowl and stir in the ginger. Season with salt and pepper. Remove the tough outer layers from the lemon grass stalk and discard. Chop the center part as finely as possible and mix into pork. Shape into four patties and chill for about 20 minutes.
Heat the oil in a large non stick frying pan and add the patties. Fry for 3-4 minutes on each side over a gentle heat until cooked through. Remove from the pan with a metal spatula and drain on paper towel, then serve.