Preheat your oven to 160 degrees.
Boil or steam the potato, and once cooked, roughly mash.
Add the mashed potato to a large bowl with the tuna, sweetcorn, herbs, spring onions, and a few grinds of black pepper. Use a fork to combine all the ingredients well.
Use your hands to form patties from the mixture. I like to make 4 small fishcakes, and serve 2 per person.
Dip the patties in the beaten egg, and then dip in the breadcrumbs so they're covered well.
Place on a baking tray, and spritz with low calorie cooking spray. Bake in the oven for 25 minutes, or until golden and piping hot throughout.
Serve and enjoy!