Combine the ingredients in a heat-proof bowl, place over a pot of simmering water and beat with a whisk until set and smooth (that'll coincide with the time your arm feels like it's going to drop off).
Stir in the horseradish and keep warm until ready to serve.
Warm the trout fillet slightly (steam oven, microwave, oven, whatever you have at hand).
Shred with a fork into bite-sized pieces.
For the scrambled eggs, heat half of the butter in a frying pan.
Gently beat the eggs and milk.
Dice the remaining butter, add to the eggs and pour into the pan.
Over a medium to small flame, cook the eggs, gently stirring with a whisk.
When they start to set, take them off the heat and continue to stir until they're cooked through, but still creamy and soft.
Fold in the trout fillet, then arrange on a plate, drizzle with the hollandaise and decorate with some dill.