Choose 2 fairly large fillets of sea bass. Purée a generous handful of olives with extra virgin olive oil until you obtain an olive paste. Roll out a rectangle of pastry and spread it with the olive paste. Place one of the fillets of fish along the short side leaving about a centimetre of pastry edge free, add some chopped olives, the other sea bass fillet and roll the pastry up, folding the extremities of pastry at either end inward to make sure the filling does not leak while cooking. Bake in a preheated oven at 200°C for 20/30 minutes. 10 minutes before the strudel is cooked, brush the surface of the pastry with a beaten egg yolk so that it turns a crispy golden brown.