Take the leaves off the watercress (keep some apart for the finishing part of the dish) and arugula and blanch for 1 minute in boiling water. Cool down immediately on iced water.

Sieve and press out the liquid. Blend in the foodprocessor with the water and olive oil. You should get a smoothy and green sauce (coulis). Proces for 10 minutes at full speed to get a nice green colour. The emperature rises during processing and this gives the green an extra dimension. Sieve the coulis.

Bring to the taste with salt and pepper and set aside.

Add both ingredients in a vacuum bag and vacuum for 60 minutes at 75ºC. Sieve and it's ready to use.

Boor met behulp van een parelboor gelijkmatige bolletjes uit de aardappel met schil. Cut small balls from the potatoes, let them unpeeled.

Make a stock of the eel bones in 15 minutes and sieve after.

Add the butter tot the stock and reduce till half. Add the potato balls and glaze until done. Keep moving the balls and let all the liquid vaporise. The balls should be done and shining.

Blend the yogurt with the horseradich oil and bring to the taste with salt. Optinonal for advanced cooking: Make pearls with an alginate bath.

Cut the smoked eel along the spine from head till tale. Keep the bone for the stock. Cut the eel in equal parts of 5 cm length. Before serving, warm to room temperature.

Cut thin slices of the big potatoes. Lay them on a paper cloth and brush thinly with potato starch. Put another slice on top of it and let is rest for 15 minutes. Stick out with rings of 1 cm. Pan fry in oil on 160ºC while moving them constantly. Serve immediately when still hot.

Warm the watercress coulis luke warm and pour into the plate. Put the eel in the coulis. Put a quenelle of the horseradich-yogurt in the middle of the plate (advanced cooking: put the pearls on the coulis) and put the two structures of potato on the plate. Sprinkle some horseradich oil on it and put some of the herring caviar on top of the eel parts. Finish with some fresh watercress tops.