Fill a large pot with water and make sure it is deep enough to reach the circulator’s marked water line. Leave enough room for the steak bags to sit fully beneath the water without crowding the pot.

Attach the immersion circulator and heat the water to 125-128°F for medium-rare steak. The water should circulate steadily before the bags go in.

Season both sides of each steak with the coarse sea salt and coarse black pepper, then place each steak in its own medium Stasher bag or FoodSaver bag. Separate bags allow water to move freely around every steak.

Set 1 tablespoon of butter and 1 herb sprig on each steak before sealing the bags. The butter and herbs will gently scent the beef as it cooks.

Press out as much air as possible and seal each bag tightly. A well-sealed bag should cling closely to the steak rather than balloon above it.

Lower the sealed steaks into the heated bath and cook at 125-128°F for 2-4 hours. After 2 hours, the centers should be evenly warmed through; stop by 4 hours to protect the steak’s texture.

Lift the steaks from the water bath after cooking and place them on a plate. They will look pale and damp at this stage, which is normal before searing.

Heat a cast iron skillet over medium-high heat, then add the olive oil once the skillet is hot. The oil should loosen and shimmer across the pan.

Sear the steaks for 1 minute per side, then remove them from the skillet right away. The exterior should develop a dark brown crust while the center remains at the bath temperature.

Slice and serve the steaks immediately after the sear. The browned crust should stay crisp while the interior remains tender and evenly cooked.