Ingredients

* 1 1/2 lbs boneless sirloin stead, 1″ thick
* kosher salt
* freshly ground black pepper
* 1 cup dry white wine (such as chardonnay)
* 2 tablespoons white wine vinegar
* 1 shallot, minced
* 1 tablespoon olive oil
* 6 tablespoons unsalted butter (1 tablespoon set aside, 5 cut small & chilled)
* 2 tablespoons finely chopped fresh tarragon

Directions

1. Preheat oven to 400F
2. Season steak on both sides with salt & pepper and refrigerate
3. Combine wine, vinegar and shallots in a small saucepan and bring to a boil. Reduce heat to medium-low and simmer until mixtrue is reduced to two tablespoons, 15-20 minutes.
4. Meanwhile, heat a large heavy ovenproof skillet over medium high heat. When it is hot add oil and 1 tablespoon of the reserved butter.
5. When butter is melted add steak and sear for 1 minute. Reduce heat and cook until the first side is golden brown and beginning to crisp, about 3 minutes longer.
6. With tongs turn the steak and sear the other side until it is brown, about 3 minutes.
7. Place pan in the oven and finish cooking, turning once. (about 6-8 minutes for medium -rare.)
8. Transfer steak to platter and cover with foil to keep warm.
9. To finish sauce put through a fine strainer, pressing on shallots.
10. Whisk the five tablespoons of cold butter a few peices at a time into warm reduction until you have a creamy sauce.
11. Stir tarragon to taste and season with salt and pepper.
12. Slice steak into half inch thick slices across grain, spoon sauce on top and serve.