Make sure to trim the meat before you start cooking. The meat can have quite a bit of fat and sinew.
Season the meat with freshly ground salt and pepper and place it in a vacuum bag.
Vacuum seal the bag and place it in the water bath.
Let the meat cook for 1 hour and 45 minutes at 55.5 degrees Celsius (41 degrees Fahrenheit). Adjust the temperature if you prefer it more rare (52-54 degrees) or medium (59-61 degrees).
Remove the meat from the vacuum bag and dry it thoroughly. I typically use a clean tea towel, but you can also use some kitchen paper. It is just important that it is dried well so that it doesn’t boil when placed on the pan/grill afterwards.
Crust the meat as desired. I used ghee on a regular frying pan, but you can also use neutral tasting oil on the hot pan and wait until it is well heated. When the meat is placed on the pan, you can simultaneously add butter in the same amount as the oil. Give it 15-20 seconds on each side. Alternatively, you can brush the meat with neutral tasting oil and put it on the charcoal/gas grill for 10-20 seconds on each side.
Slice the meat and sprinkle good flaky salt over it. The meat does not need to rest before slicing.
Serve immediately. Enjoy.