1. In a non-stick skillet or saucepan, melt the butter. Over high heat, add the leeks, well washed and finely chopped. Salt. Cook 10-15 min over medium heat covered, stirring occasionally.
2. Deglaze with a trickle of Noilly Prat and continue cooking 5-10 min to evaporate the alcohol and obtain a very tender leek fondue.
3. In parallel, heat the cream in a saucepan to make it reduce and thicken slightly. Add the chopped parsley, and a little finely chopped garlic according to taste. Adjust the seasoning by pepper and adding a pinch of nutmeg.
4. Pour a little liquid cream into the leek fondue and mix well.
5. Pour 1/3 of the remaining liquid cream into the bottom of a baking dish. Place 1 or 2 plate (s) of ravioli - depending on the dimensions of your mold - to line the bottom of the dish like lasagna. Cover with a little leek fondue. Alternate the ravioli and leeks until all the ingredients are used up, ending with a plate of pasta. Pour the rest of the parsley cream (2/3) over the gratin, and sprinkle with grated Comté cheese.
6. Bake for a few minutes (15 to 25 min) under the grill in an oven preheated to 190 ° C. Watch the cooking; the gratin is ready when it is well colored and golden. Enjoy immediately with fresh salad.