1. Peel and chop the sweet potato. Add to a pan and simmer for 20mins.
2. Drain the sweet potato and mash.
3. Add the chopped spring onion, tuna, lime juice soy sauce, garlic and salt and pepper to the pan with the mashed sweet potato. Mix through.
4. Divide the mixture into 6 equal measures and shape into patties/fishcakes.
5. Coat each fish cake in the oat cereal and gently fry the fishcakes in a frying pan with some coconut oil.