For the pancakes, stir together the flour, eggs, milk and salt until you get a smooth batter. (Part of the milk can also be replaced with mineral water. This loosens the dough a little.)
Bake about 8 thin pancakes from the pancake batter in a pan with a little butter. This e.g., cut out with a cake ring so that all pancakes are the same size. Place the pancakes on a wire rack to cool.
In the meantime, stir the filling for the cake. Finely chop the spring onions and dill. Mix both in a bowl with cream cheese, crème fraîche and horseradish. Season the filling with salt and pepper. If you want, you can add a little lemon juice.
Place a pancake on a plate and put a cake ring around it. Spread a layer of the filling on the pancake and place a layer of salmon on top. Repeat this until all of the pancakes are layered. As the last layer, apply another layer of the cream cheese cream.
To decorate, you can spread a piece of salmon or dill on each of the cake pieces.