Croquettes from leftover souvla and potato

For the mixture

2 medium baked potatoes (about 350 g), mashed 100 g souvla chicken, finely chopped 1 egg 50 g graviera cheese, grated 50 g mozzarella, grated or cut into very small cubes 1 tbsp chives, finely chopped 15 g cornstarch (1 tbsp) zest of ½ lemon 1/2 tsp sweet paprika salt pepper

For the coating (without egg)

50 g flour 1 egg, beaten 100 g panko breadcrumbs

For frying

½ liter sunflower oil