Filet Mignon With Dijon Sauce - With pork

1/2 lb white mushroom , cleaned and sliced thin 1/4 cup olive oil 1 medium onion , chopped 1/4 lb prosciutto or 1/4 lb pancetta , chopped 1/3 cup beef broth[...]

4 filet mignon 4 portabella mushrooms (stemmed&gills scraped) 2 tablespoons olive oil 3 tablespoons red wine vinegar 1/4 teaspoon salt and pepper 1 for steaks[...]