Fish fillets other than salmon can also be used (e.g. trout, cod or halibut).
Preheat the oven to 200°C. Wash the potatoes well and cut into thin slices. Then parboil in boiling salted water for a few minutes until al dente. Drain in a colander and rinse with cold water. Halve the leek lengthwise, wash well, pat dry and cut into fine strips. Peel and finely chop the onion and garlic and gently fry with the leeks and peas with a drizzle of olive oil and the butter in a large cocotte on a low heat for 10 minutes.
Remove the cocotte from the heat. Cut the salmon into suitable pieces and place on top of the vegetables. Chop the anchovies finely and mix with the cream and about half of the Parmesan. Season with salt and freshly ground pepper and pour the mixture over the salmon. Mix the potato slices with a little olive oil, salt and pepper and place in layers on top. Bake in the oven for 15 minutes.
Mix together the breadcrumbs and remaining Parmesan and sprinkle on top of the pie. Bake for a further 10 minutes until the fish pie has a golden crust. Serve with freshly chopped dill and lemon wedges.