The finished recipe. Tuna and Potato Cakes with PeasIngredients 1 to 6. 120 g Tuna in spring water, drained (Drained weight. Tuna in oil is about 190 kcal per 100 g even after draining.). 150 g Potato (Raw, peeled weight.). 1 large, about 55 g Egg. 20 g Spring onion. 8 g Cornflour (Dusting the cakes in cornflour rather than breadcrumbs keeps gluten out of the dish and gives a thin crust that shatters.). 6 g Olive oilIngredients 7 to 9. 100 g Frozen peas. Of half a lemon Lemon juice. A handful, chopped Fresh parsleyStep 1. Boil the potato in chunks until tender, drain, and mash it dry with nothing added.Step 2. Mix the mash with the drained tuna, spring onion, parsley, beaten egg, salt and pepper. Shape into three cakes and chill for twenty minutes.Step 3. Dust the cakes in the cornflour and fry in the oil over a medium heat for four minutes a side until deep gold.Step 4. Boil the peas for three minutes and serve with the cakes and lemon.