Preheat the oven to 180°C.
Place the salmon steaks on a baking tray lined with baking paper. Brush them with olive oil and season with salt and pepper.
Cook in the oven for 15 minutes.
While they are cooking, finely chop the shallots. Brown them in a frying pan with a little olive oil. Set aside.
Melt the butter in a saucepan, then add the flour and whisk to make a roux. Slowly pour in the ALSACE LAIT Label Rouge crème fraîche from Alsace for pouring, stirring constantly with the whisk until the mixture thickens. Season with salt and pepper, and add a pinch of ground nutmeg. Mix well.
Flake the salmon.
Place a third of the salmon in a gratin dish, add the fresh spinach leaves, chopped dill and shallots, then generously spread with a third of the cream. Place 4 sheets of lasagne on top and repeat the process twice more. Once the layers are complete, sprinkle the dish with grated Emmental cheese.
Bake in the oven at 180°C for 25 minutes. Enjoy!