Add water to the sous vide container or a large pot, set the Sous Vide Precision Cooker to (135°F/57°C) for medium-rare doneness.
Rub the steak with 1 tablespoon oil on all sides.
Season with salt and pepper.
Add the steak to a zip-top bag together with optional herbs.
Vacuum seal the bag using water displacement method: seal all but one corner of the bag, and slowly place it into the water bath. Make sure everything below the zip-line is covered by water. Then seal the rest of the bag.
Keep the bag in the water bath and make sure it is fully submerged.
Cook for 1 hour. If your steak is thicker, cook 2 hours for 1.5 –inch, and 3 hours for 2.5 hours.
When the timer goes off, remove the bag from the water bath and transfer it to the fridge or an ice bath. Let it chill for about 10 minutes.
Remove the steak from the zip-top bag and wipe off the moisture with paper towels. (Make sure to pat dry the surface completely.)
Season with more salt and pepper if necessary.
Place the cast-iron skillet on medium-high heat. Add the remaining olive oil. Once very hot, add the steak and sear about 1 minute per side until nicely browned.
Slice against the grain and serve immediately.