Fill a vessel with water (ensure it is large/deep enough to hold the steak). Attach your sous vide and set the temperature to 130 degrees F. (for a medium-rare finish). 

Pat the steak dry with a clean paper towel. 

Season generously with kosher salt and ground black pepper. 

Place steak inside a Stasher reusable bag (a ziploc bag works too) along with 1 tablespoon of butter (per steak) and a sprig of fresh rosemary and thyme. You should use one bag per steak. 

Remove as much air as possible and seal the bag completely and place into the water. Feel free to place a small saucepan on top to ensure the bags are fully submerged.

Let cook 2-4 hours. 

Remove from water and take the steaks out of the bag.

Bring a large cast iron skillet to medium-high heat. Add the remaining two tablespoons of butter. When the skillet is nice and hot (it should sizzle if you flick water on it) place the steaks in the skillet and sear each side 30 seconds - 1 minute.  

Remove and let rest 5-10 minutes. 

Serve with some Homemade Chimichurri or this Creamy Horseradish Steak Sauce if you want to take it to the next level!