For the fennel gratin with potatoes, pour the milk into a pot and season with nutmeg, salt and pepper. Peel the potatoes, cut into 3-4 mm thick slices and add to the milk. Simmer on low heat for about 7-8 minutes, stirring frequently to prevent anything from sticking. Remove from heat.
Wash the fennel, cut in half and cut into pleasing pieces or strips. Heat some butter and/or olive oil in a pan and sauté the fennel in it. Pour in a generous splash of white wine. Let it boil down, add a squeeze of lemon juice and then add a little vegetable soup. Season with salt, pepper, fennel powder and cumin to taste and simmer until half cooked.
Peel the eggs and cut them into slices. Butter a suitable baking dish and layer the potatoes alternately with the fennel. Spread the egg slices in between and cover with vegetables. For the topping, whisk the milk with crème fraîche or whipped cream, season with salt and pepper. Stir in about half of the cheese and heat briefly over medium heat until cheese is melted. Pour over casserole. Sprinkle the remaining cheese over the fennel gratin with potatoes and bake in a well-preheated oven at 180 °C for about 40 minutes.