Peel and finely chop the shallots; wash and finely slice the leeks.
Finely grate the Comté or Beaufort cheese.
Preheat the oven to 180°C.
Melt the butter in a frying pan, add the shallots, and sauté for 3 minutes.Add the sliced leek whites and continue cooking, covered, over low heat for about ten minutes, until tender. Sprinkle with flour and stir.Add the milk and mix for 2 minutes.Add the liquid cream (reserving a small amount) and stir in a Picodon cheese cut into pieces, along with the chopped parsley.Heat gently over low heat for 3 to 5 minutes, stirring constantly. Assemble the dish in successive layers, just like lasagna.Pour the reserved creamy base into the baking dish, then arrange a layer of ravioles.Spread out some of the leek fondue, sprinkle with a little grated cheese, and add a few pieces of Picodon.Repeat the process, alternating layers of ravioles, leeks, and cheeses until all the ingredients are used up.Finish the gratin with a layer of grated cheese. Bake for 15 to 20 minutes, until the top is golden brown and gratinated.
