Filet de Bouef Grillé avec Mignonnette de Poivre (Grilled Filet of Beef with Pepper Sauce)

French chef Joel Guillet served us his Provençal version of the classic steak au poivre when we visited him, years back, at Le Mas du Langoustier, on France's Île de Porquerolles, off the Mediterranean coast near Toulon.