I got the idea for this from a recipe book cunningly titled "The Burger". It includes grated courgettes which I don't like, and is served with a mango salsa, which I couldn't be bothered with, so this is just a plain tuna burger. It's easy to make and is a nice chance from a beefburger. It is also a different way to use up leftover mashed potatoes.
Put a tuna steak in a food processor and chop.
Add some chopped spring onion, a little chopped red chilli if desired, and some leftover mashed potatoes.
Finally add 1 tbsp of mango chutney and pulse until blended.
Turn the machine off, then remove the mixture from the food processor and shape into a patty.
Fry in some Fry Light and serve either in a bun or naked, with French fries or some veg.