Drain and rinse the kidney beans in cold water to wash away the ‘tinned’ taste. Put in a saucepan and cover with cold water. Bring to the boil, then simmer for ten minutes to soften. In a separate pan, add the finely chopped onion, grated carrot, cumin and coriander. Drizzle a little oil over and cook gently on a low heat to soften.
When the kidney beans have heated through and softened, drain and add to the carrots and onions. Mash together with a masher or a fork until you have a smooth-ish purée (like a mashed potato consistency). Stir in a heaped teaspoon of flour.
Heat a little oil in a frying pan on a medium heat. With floured hands, shape some of the mixture into a ball, about the size of a golf ball. Place in the oil and flatten gently with a fork to make the burger shape. Cook for a few minutes on one side, before turning over gently. They need to be handled with care while cooking as they can be quite fragile!
When cooked on both sides, serve hot.