Mix all ingredients together thoroughly in a mixing bowl.
Flatten out the mixture onto a board until you have a 3cm thick layer.
Cut out burger shapes with a biscuit cutter (or a hollowed out old tuna tin).
You will probably get 2-4 burgers depending on the size of the cutter.
Cook the burgers for 3-5 minutes on each side for a medium burger on a griddle pan, a little longer if you refer the burger more well done.
Place the burger in the bun (toasted if you prefer) with some lettuce, sliced tomatoes and sliced onion rings.