Boil the potatoes.
Drain the oil from the canned tuna.
When the potatoes are cooked, start with the mixture. In a large bowl, mix together the potatoes, spinach, tuna, grated cheese, garlic & parsley. Season everything with some salt & pepper.
Mash the ingredients well with a potato masher. Start forming the patties.
Preheat the oven to 175C.
Heat up the oil in a frying pan. Start frying the patties by cooking them for 5 minutes on each side over medium heat.
When they are cooked transfer them onto paper towels to drain the excess oil from them.
When done cooking all the patties, put them on a baking paper in a baking dish & cook them in the oven for 10 minutes.
Serve them with salad, bread or to your preference.