Score the fat layer crosswise with a sharp knife.

Season the meat with freshly ground salt and pepper on both sides.

Vacuum seal the meat and place it in your sous vide.

Cook the meat for 4 hours at 56 degrees Celsius (133 degrees Fahrenheit). If unsure about the quality of your lamb rump, give it 5 hours. If you prefer it well-done, simply set the temperature to 60 degrees Celsius (140 degrees Fahrenheit).

Take the bag out of the water bath and remove the meat from the bag.

Dry the meat thoroughly. I usually use a clean tea towel for this, but paper towels can also do the job.

Heat a pan until it is as hot as possible (do not use a Teflon pan, as they typically cannot handle high heat).

If you have ghee, I find it the best for frying. Add it to the smoking hot pan and fry the meat for 30-60 seconds on each side. If you have "only" butter and oil, add the oil to the hot pan. Once the oil is hot, add the butter and meat simultaneously. Be careful not to let the butter burn.

Slice the meat into thin pieces, sprinkle with flake salt, and serve immediately. Enjoy.