How to Make It
In a small saucepan, cover the eggs with cold water and bring to a rolling boil. Cover, remove from the heat and let stand for 7 minutes. Drain the eggs and cool under running water, shaking the pan to crack the shells. Drain again and pat dry, then peel and coarsely chop.
Meanwhile, in a small bowl, mix the mayonnaise and horseradish and spread on the bread. Arrange the radishes on 4 of the slices and top with the sprouts, scallions and salmon. Spoon the eggs on top, season with salt and pepper and close the sandwiches. Press gently, cut the sandwiches in half and serve.