Preheat oven to 200 ° C. Season the bechamel with a little nutmeg. In a bowl, mix the cream, ricotta, salmon and parsley and season to taste. Insert a spoon into a pastry bag. Cut a slit in the Lyonnaise and fill them.
Put Lyonnaise in an ovenproof dish, sprinkle with Parmesan and pour spoonfuls of bechamel on top. Bake for about 10 minutes and serve.