Determine your desired doneness for your steak from the chart below.Make note of the THICKNESS of the steak. This will determine the length of the cooking time. Count on one hour of cook time per inch of meat in thickness.
Truss the steak around the circumference of the cut with a piece of kitchen twine, if desired.
Set your sous vide machine to the desired temperature, allowing it to heat up while you prepare the meat for sous viding.
Preheat a heavy bottom pan or a cast-iron skillet to the point of smoking.
Lightly brush your steaks with the high heat oil of your choice or drizzle a few tablespoons in the bottom of the screaming hot skillet.
Sear on high heat for one minute per side. Do not move the meat once it comes in contact with the pan. You don't want to break the sear until you are sure you have the color you want.The steaks will easily pull away from the pan when they have been properly seared with a nice crust.Once the steaks have been preseared, remove them to a clean plate. Turn off the heat and deglaze the pan with a few tablespoons of butter, add minced fresh garlic and herbs. Quickly cook the garlic and the herbs. If the foaming butter cooks away, add a splash of stock, wine, or water to help loosen the fond from the bottom of the pan. Cook for 1 hour per inch of thickness.
After cooking remove the steaks from their cooking bag to a clean plate patting them dry with clean paper towels. Reserve the juices, or purge, from the bag to be used in a pan sauce if you are making one.
Reheat your cast iron pan to smoking hot and sear the steaks on both sides, bringing back the amazingly flavorful crust.
Transfer the sous vide steak to a serving plate and make the sauce.
To make the sauce add 3 tablespoons of butter to the hot pan, scrape the fond from the bottom of the pan, add the juices from the sous vide bag. To stretch your sauce add ½ cup to 1 cup of stock or red wine to the pan.Allow the sauce to reduce and thicken.
Spoon the sauce around the steaks, top with salt and black pepper. I also will add a pat of butter for extra richness.