3 large leeks (white parts only, halved lengthwise)
1 tsp ground fennel seed
sea salt and coarse black pepper
2 large fennel bulbs (quartered lengthwise)
4 cloves of garlic minced
2 tblsp fresh herbs (parsley, thyme, marjoram)
1 cup fresh cream
1 bay leaf
0.5 tsp peppercorns
0.5 tsp fennel seeds
3 sprigs of thyme
3 sprigs of parsley
2 oz mature white cheddar (grated)
2 oz parmesan cheese (grated)
1 ½ pounds waxy potatoes
12 pitted black olives (coarsely chopped)
Heat the olive oil in a pan and add the leeks, ground fennel, pinch of salt, and a little pepper. Sauté over a medium heat until the leeks are softened, about 5 minutes.
Thinly slice the fennel bulbs and add it to the pan, along with the garlic and a pinch of salt. Sauté for 5 minutes until the fennel is tender.
Set aside in a bowl and toss with ½ the parsley, thyme, and marjoram.
While the leeks are sautéing, pour the cream and milk into a small pot; add the bay leaf, pepper corns, whole fennel seeds, and sprigs of herbs.
Simmer over a low heat for 20 minutes.
Pour through a strainer and season with a little salt.
Preheat the oven to 375°F. Lightly oil a 9x13 inch baking dish.
Mix the cheeses together.
Thinly slice the potatoes and layer 1/3 of them in the bottom of the baking dish, overlapping the slices.
Season with salt and pepper.
Sprinkle with the olives, half the leeks and fennel and 1/3 of the cheese.
Layer half of the remaining sliced potatoes on top. Season with salt and pepper. Place the rest of the leeks and fennel on top, and ½ of the remaining cheese. Top with a final layer of potatoes and pour the hot cream over.
Cover the dish and bake for 40 minutes.
Sprinkle with the remaining cheese and bake, uncovered, until the potatoes are very tender and the gratin turns golden and a little crisp, approx 15 minutes.
Sprinkle with the remaining chopped herbs just before serving.