In a pan, add the olive oil and sauté the onions. Add the garlic and continue sautéing. Add the shrimps and cook for 1-2 minutes from each side, until their colour changes. Add the zivania, torch the alcohol and let it evaporate.
Remove the shrimps and add the tomato paste, rubbing it onto the base of the pan to release its aromas. Add the tomato Passata, stir and boil for 4-5 minutes. Add the chili flakes and the salt and stir. Add the chicken stock and boil until the water evaporates. Stir and return the shrimps into the pan. Cook for 1 minute and turn over. Crush the Feta cheese on top, sprinkle with the parsley and serve.