Hand grate the zucchinis/courgettes, onion and potato and keep on the side in a sieve for 30 minutes with a ½ teaspoon of salt added. Place in a kitchen towel and squeeze tightly to remove the excess water.
Place the squeezed veggies in a bowl and add the feta cheese along with most of the chopped mint and all the parsley, the whisked eggs and cumin and season with the remaining salt and pepper. Fold carefully and place in the refrigerator for 30 minutes.
Take out of the refrigerator and add the flour, the baking powder and mix gently as you want your mixture to remain light.
Put a cast iron frying pan on medium heat, add the oil and heat up without burning. Spoon (with a tablespoon) from the mixture and carefully add to the pan without overcrowding it. Use a spatula to gently flatten the fritters and cook for about 6 minutes, tossing halfway through. Your fritters should be both crisp and golden colour. Repeat the above for the remaining mixture.
With a slotted spoon take off the pan and place in a tray lined with a wire rack to allow some of the oil to drain. Serve while drizzling some of the sauce on top and sprinkle with the remaining mint.