Clean and cut up your fish into even lengths. This can vary depending on the fish you use.
If using fresh oregano, remove the leaves from the stalks and chop leaves very finely.
Set up a station with three bowls. Half the flour in the first one, beaten eggs in the second one and remaining flour mixed with oregano, lemon zest and pepper in the third bowl.
Dip each fish fillets in the same order, flour, egg and herb flour again. Set aside
You will need to clarify the butter, simply add to a saucepan, melt on low heat and remove any foamy impurities leaving butter milk on the bottom. Scoop out the top layer of fat leaving any buttermilk on the bottom. Place all the clarified butter in a large frying pan.
Add medium heat to the frying pan, add the fish, (do it in two or three batches) and fry approx. one minute on each side until golden brown. Season with salt and serve immediately.
Garnish with a wedge or cheek of lemon, and a sprig of parsley or oregano.