Peel the membrane of the liver and remove the nerves from it. Then cut it into small cubes. If your butcher does it for you, then skip this part. Make sure to ask your butcher when the liver was delivered. It is important that the liver is fresh.
Wash and drain well the liver. Then pat dry with paper towels.
Put the liver pieces in a bowl and sprinkle salt, red pepper flakes, paprika and cumin. Toss to blend.
Sprinkle the flour on top of the liver using a tea colander. Shake well so that every piece is coated with flour and separated from each other. Transfer the liver to a sieve and toss out the excess flour.
Put enough liquid oil to half fill a deep pan. Heat the oil and fry the liver.
Fry in small portions so the heat is always high and they do not stick to each other
Liver will be ready very quickly – in about 2 minutes. Do not fry too long or else the liver will become dry and will be difficult to eat. The outer side should be crispy and the inside soft.
Take out the liver using a perforated scoop first to a plate with paper towels, to get rid of the excess oil.
Better, when served warm.
Garnish with the onion mixture, some chopped parsley and a lemon wedge and tomato slices - as you like.