Rinse the filet in cold water and dry well with a thick paper towel, on both sides of filet. Leave the fillet in a clean glass or porcelain dish, skin down.
Mix salt and sugar, sprinkle over the fish fillet. Leave a stem of fresh tarragon on top. Make sure the tarragon is well cleaned! In case of soil, or rotten spots remove these parts. Pour gin over.
Put the fillet in a vacuum bag or cover the form with cling film and place in a cold place (max 4 degrees Celsius) for two days. Be careful to keep cleanliness.
Take away the tarragon and wipe of the salt/sugar and dry the fillet with a paper towel. Slice the cured fillet in thin slices and assemble on a plate. Make the topping of finely sliced red onion and shaved fennel, add vinegar and olive oil. Mix in some fresh chervil right before serving. Place topping on top of the Sterling fillet.
Happy cooking and enjoy!