With a pestle and mortar crush the peppercorns. It's okay if some pieces are bigger than the others. Put your pepper in a bowl.
Finely chop your rosemary and add it to the pepper.
Now add the salt and sugar and mix.
Lay down some wrapping paper and put your fillet in the middle.
Now add your mixture and rub it thoroughly on your fillet. Make sure it spread evenly.
Close the wrapping paper on the fillet and make sure that it is tightly wrapped as it will release a lot of water in the process.
Put your wrapped fillet on a baking sheet and move it to your fridge. It needs to stay there at least 12 hours to a maximum of 24 hours.
On the next day, unwrap your fillet and rinse thoroughly as it is very salty.
Using a very sharp knife, cut diagonally to make very thin strips.
You can enjoy this on top of a bagel with some cream cheese, with some homemade sushi or just as is !