Arrange a layer of the potatoes in the base of a baking dish. Sprinkle over half of the salmon then add the remainder of the potatoes.
In a saucepan over a medium heat, melt the butter then add the garlic and shallots. Cook and stir for 2 to 3 minutes until fragrant then pour in the cream and add the lemon juice, capers, nutmeg, chives, dill and seasoning. Cook and stir for 3 to 4 minutes until warmed through. Stir through the remainder of the salmon, then pour over the potatoes. Sprinkle the Parmesan cheese on top.
Bake in the oven for 60 to 90 minutes or until the potatoes are tender and soft. Cover with tin foil if the cheese begins to get too brown on top. Remove from the oven and serve piping hot.