Clean the leek, wash and cut into slices. Heat the olive oil in a pan and fry the sliced leek a bit. As soon as it’s soft, add the washed & cut mushrooms, salt and fry for a few minutes until the mushrooms are cooked.
Melt the butter in a pan, add flour, whisk together and add the hot liter of milk, little by little.
Salt the Béchamel sauce, add nutmeg and cook until thickened. Set aside two tablespoons of mushrooms and leek, stir the rest into the Béchamel.
Cube the "King of the Dolomites" and mix it with the Béchamel and the pre-cooked noodles, leaving a few cubes on the side.
Fill a buttered casserole dish with the mixture, then sprinkle grated hard cheese, a bit of leek and fried mushrooms, the rest of the cheese cubes and a few dabs of butter.
Bake in a preheated convection oven at 160°C for 30 minutes.