1) Put the onions, carrots and swede into a clean thin tea towel and twist to remove as much liquid as possible.
2) Scrape vegetables into a bowl.
3) Add salt and pepper to taste and mix well.
4) Add the egg and stir all to combine.
5) Heat the oil in a frying pan over a high heat.
6) Divide the mixture into 2 and spoon into the pan and flatten with a spatula.
7) Brown on one side for a couple of minutes and turn to brown on the other side.
8) Turn the heat down a little and allow to cook for a further 10 minutes turning once.
9) Serve immediately.