If you are using whole fish, make 3 deep cuts on each side, then rub with
Wash the watercress thoroughly and remove any tough stems. Then spin dry in a salad spinner or drain well in a colander. Finish by drying in a clean linen towel.
Heat a wok or large frying pan over high heat until it is hot. Add the
Clean the wok and reheat it over high heat. Add the remaining oil. While the oil is heating, remove the fish from its marinade and dry with the kitchen paper. Dust with flour, shaking off excess. When the oil is very hot, slowly add the fish or fillets and deep-fry them for 5 minutes until they are golden brown. Remove the fish or fillets with a slotted spoon, drain immediately on kitchen paper and serve on top of the stir-fried watercress.