Fill stockpot or sous vide container 3/4 full of water. Place on heat-proof surface and add immersion circulator. 

Heat water to temperature based on your preferred doneness for your steak. (126 degrees F = rare, 129 degrees F = medium-rare, 133 degrees F = medium, 140 degrees F = medium-well, 147 degrees F = well done).

While water is heating, season steaks and place them in a single layer in a 1-gallon plastic zip-top bag. (For three steaks, I placed two steaks in one bag and one steak in another bag.) Add a drizzle of olive oil. 

When water is heated, lower each bag into the water making sure the meat is fully submerged. Fold top of bag over the side of the stockpot. Clip bag to the side, if needed.

Set timer for cook time. Cook time depends on thickness of your steak (1/2-inch = 30 minutes, 1-inch = 60 minutes, 1 1/2-inches = 90 minutes). 

After cook time is finished, remove bags from sous vide and remove steaks from bag. Preheat heavy skillet over high heat. Place 1 Tbsp butter or olive oil in skillet then sear steaks 1 minute on each side.