Start by cutting away most fat and tendons from the pork tenderloin. There is a large and long tendon at the top of the tenderloin that needs to be removed.
Season the tenderloin with salt and pepper, and fry it on a very hot frying pan for maximum 1-2 minutes. We want a crisp outside and raw meat inside.
Place the tenderloin in an oven proof pan. Preheat the oven to 160 C (320 F) and cook it for 10 minutes.
After the 10 minutes of cooking, take the tenderloin out of the oven and let it rest on the kitchen table for 10 minutes. Continue with the 10 minutes of cooking and 10 minutes of resting until the core temperature is 55-60 C (130-140 F). This should take about 3-4 cycles, however the temperature is the important factor.
When the core temperature is reached let the tenderloin rest for about 5 minutes and then cut it in nice and thick slices. Serve right away.