Cut the fillet in two. Mix breadcrumbs (rasp) with parmesan, parsley, lemon zest and salt & pepper in a plate. And beat the egg.
Dip the fillet first in the egg, then in the breadcrumbs mix, and then fry on a hothot frying pan with 1 cm olive oil.
Fry the fillets only for 2-3 minutes. Remember to turn them. They need to be golden on both sides.
While the fillets are frying, mix tartare sauce, a squeeze of lemon, capers, and parsley – and spread a layer on the bread (maybe toasted), then the hot fish some fresh coriander and bread on top. You can choose to serve the sandwich lemon wedges and fries.