Prep. time: 15 minutes
Cooking time: About 1 hour

1. Cook the potatoes in boiling water.
2. Cool and peel, then cut two nice rounds from the centre of each one. Set aside at room temperature.
3. Clean the leeks, keeping very little of the green parts. Wash and halve lengthwise (or quarter in the case of a large leek.)
4. Cook the leeks in boiling salted water, then cool by immersing in ice water to set the colour. Drain and cut into chiffonade (thin slices). Set aside in a cool place.
5. Place the cream and beer in a saucepan and reduce by half over low heat. Season lightly with salt and add the shallot and oil.
6. Combine and season the leeks with this sauce.

Presentation

1. On each plate, place a potato round and cover with a layer of leeks. Top with a spoonful of caviar.
2. Garnish with a sprig of chervil.