Ready in: 1h Serves: 2 Complexity: medium Origin: Main Dishes
1 white onion, peeled and cut crosswise into thin round slices
2/3 cup clarified butter for sautéing
6 (7-ounce) slices of sirloin
1/3 cup cognac
¼ cup tarragon vinegar
1 cup brown beef stock
1 tablespoon butter
1 tablespoon Dijon mustard
salt and freshly ground white pepper to taste
1. Heat oil deep frying. Meanwhile, dip the onion slices in some flour and pat to remove the excess. When oil is hot, fry onions until they are golden.
2. Remove the onions from the oil, drain on paper towels, and keep warm on the stove top – Heat 2/3 cup clarified butter in a skillet and sauté the sirloin slowly over medium-high heat until brown outside and medium-rare inside. Keep the sirloin warm on a covered plate.
3. Degrease the skillet by wiping it out with a paper towel and add the cognac and vinegar. Reduce almost all of the liquid. Add the beef stock and reduce by half. Lower the heat.
4. Whisk in the butter and mustard at the same time. Be sure to whisk well to avoid having clumps of mustard. Add any meat juices from the sirloin on the covered plate and stir well. Season with salt and pepper to taste.
5. Place the meat on warm plates. Pour the sauce over the meat and sprinkle with fried onions.
Image: © By Kobako (photo taken by Kobako) [CC BY-SA 2.5 (http://creativecommons.org/licenses/by-sa/2.5)], via Wikimedia Commons - https://commons.wikimedia.org/wiki/File%3AZwiebelrostbraten.jpg