(*) For a gratin dish of about 23×33 centimeters, enough for four people.
Anne Sommerville: This tasty winter dish is prepared with enough leeks, aromatic fennel and fruity olives. We often serve this gratin on a bed of green leaf lettuce (mizuna, arugula or frisée lettuce) – the lettuce leaves fall together due to the temperature of the gratin and unite in themselves all the fantastic flavors of the dish.
For the vegetable mixture, heat the olive oil in a large frying pan. Pour in the leek strips, ground fennel seeds, half of the salt and a tiny bit of pepper. Heat the leeks over medium heat, cover and drop together (about five min). Add the fennel, garlic and remaining salt and saute for five min. Transfer the vegetables to a suitable bowl and mix with the chopped herbs.
In the meantime, cook the seasoning cream: pour the whipping cream and milk into a saucepan. Flavor with the bay spice, peppercorns, whole fennel seeds and herb sprigs. Simmer on low heat for twenty minutes. Pour through a sieve and season with salt.
Preheat the oven to 190 °C. Lightly oil the gratin dish. Mix the two cheeses. Finely slice the potatoes.
Spread the bottom of the gratin dish with one third of the potato slices. Layer the slices and rows on top of each other like a shingle. Season generously with salt and season with pepper. Add the olives and