Preheat the oven to 500 degrees.  Season the salmon on both sides with the salt and pepper.  Spread the mustard on the “pretty” side of each fillet. Sprinkle each fillet with bread crumbs and use your hands to press the crumbs into the mustard.  Heat the oil and butter in a large oven-proof skillet over high heat.  When it begins to smoke, add the salmon mustard side down.  Turn the heat down to medium and sear the fish for 2 minutes. Turn and sear the other side for 1 minute.  Transfer the skillet to the oven bake for about 3 minutes.