Place garlic and cilantro in food processor and puree, then add oil in a stream while blending, then add remaining ingredients and process until well blended, this mixture will be thick. Coat the Filet Mignons with puree and marinate overnight. Scrape off excess marinade and grill on a hot grill to sear and then move to a medium heat to finish to desired doneness. Let rest for 5 minutes before serving.
Sweat the onions over medium heat in the oil. Add the garlic and pepper and sauté for 1 minute, then add the wine and reduce by half. Off the heat, add the chocolate and bullion cube and stir until completely melted and absorbed (you can puree this sauce if you like with a blender). This sauce has very intense flavor and just a little on the filet is best and quite delicious.