Place your mash into a bowl, add the cheese, flour and egg and mix until combined.
Pour a layer of flour over a large plate. Grab a second plate, ready for the cakes (or place them straight in the pan). Heat the oil in a frying pan. Layer two pieces of kitchen towel on another plate for when the cakes come out of the pan.
Using a spoon to scoop, spoon out large amounts of potato, dip your hands into the flour and shape into balls, flattening with your hands. Fry, two at a time, in the pan. 2-3 mins each side or until golden brown. Place on the paper towels to soak up the oil. Continue until you have 6 cakes.
Serve hot with sour cream!