We start preparing the potatoes: peel them, rinse and boil them in salted water for about 45-50 minutes, until tender. Then strain and mash them. Put the mashed potatoes in a bowl and allow cooling for about 10 minutes.
Then we add to the bowl the egg yolks lightly beaten, the parsley, “graviera” cheese, “kasseri” cheese, nutmeg, a pinch of salt and pepper to taste. Knead to combine. We cover the bowl and put it in the fridge for 1 hour, for the mixture to stiffen.
We remove the bowl from the fridge, take about 2 tablespoons of the mixture and shape into oval “patatokroketes”. Continue with the remaining mixture. Then we dust them with flour and shake to remove excess.
For the coating, lightly beat the eggs in a bowl and place the bread crumbs in a dinner plate.
First we dip the “patatokroketes” into the eggs and then coat them with the bread crumbs. Put them onto a platter, cover with plastic wrap and place them in the fridge for at least 1 hour, for the coating to settle.
Afterwards, we heat in a deep large frying pan plenty of olive oil and fry the “patatokroketes” in batches, until evenly browned. Remove them onto a paper towel, to drain excess olive oil. When the first batch of “patatokroketes” are fried, lower the heat to medium, to avoid burning the outside, since the oil is already hot from the previous batch.
We serve the “patatokroketes” garnished with parsley sprigs.