Cook your steak in a stainless steel pan. While it's resting, wipe away any burned bits. If there's a lot of oil and grease, remove all but a few tablespoons. Put the pan back on high heat.

Add the shallot and garlic to the pan and sweat for 1 minute. Be careful not to burn the garlic. Off the heat, pour in the brandy. Put the pan back on the heat and scrape any goodness from the bottom of the pan. Let all but a few tablespoons of liquid boil off.

Add the vinegar and stock and continue boiling until there's about 1/4 cup of liquid left. Add a pinch of salt and a few grinds of black pepper. Take the pan off the heat and add the tarragon, cream and any juices that have come out of the steak. Stir until the sauce is uniform. Pour the sauce over the steak or serve it on the side.