Afterwards, de-glaze the pan with beef stock and cognac, when halfway reduced add some heavy cream (Ronnybrook farms non-homogenized if available) and let reduce a bit more at a lower heat setting. When sauce thickens, fortify with European style butter and spoon over the steak.
You can also reverse sear by cooking steak to 125 degrees in the oven at about 275 for 40mins or so and then searing for one minute to a minute and a half on each side in the hot pan to finish. Either way it comes out perfectly if you control your temperature properly.