Preheat the oven at 200 degrees.
Cut the potatoes into thin slices, about 2 mm thick and place them next to eachother on a baking tray covered in baking paper and spray with olive oil and a bit of salt. Bake for 20 minutes in an electrical resistance oven.
Wash and cut mushrooms into thin slices.
Place a non-stick pan on the heat and wait for it to warm up well. Then pour a little bit of olive oil and one tablespoon of fresh butter and lightly fry the mushrooms along with a clove of garlic and the rosemary until the juices come out.
When ready, remove the garlic and rosemary and leave aside.
Crack the four free range GOLDEN EGGS with Omega 3 in a bowl, adding the milk, a little bit of nutmeg and pepper and mix using an egg whisk.
Butter an ovenproof dish 25cmx35cm well and make a layer of the baked potatoes, overlapping and covering the bottom of the dish.
Spread half of the mushrooms over the potatoes and then cover with half of the smoked turkey fillet.
Next, sprinkle the grated cheese mixture over the whole surface of the dish.
Pour half of the egg and milk mixture over the au gratin, making sure that the whole surface is covered.
Next, make a second layer exactly like the first and pour the rest of the egg and milk mixture over it.
Put all the ingredients for the yoghurt sauce into a deep bowl and mix using an egg whisk.
Pour the mixture over the au gratin, making sure that the whole surface is covered, and smooth it down with a spoon.
Sprinkle the grated parmesan over the au gratin.
Bake in a pre-heated oven at 180 degrees for 60 minutes, or until golden brown.
Allow it to cool and serve.
