Season salmon with salt, pepper and Worcester sauce, place on a baking tray. Grind the cooked potatoes, mix with horseradish, cream, egg yolk and salt. Spread the potato-horseradish mixture on the salmon fillets with a pastry bag (star shape). Bake in oven heated to 180 degrees for about 20 minutes.
For the sauce, sauté finely chopped shallots in butter, add white wine, fish stock and cream. Boil sauce, bind (assemble) with ice-cold pieces of butter and season. Blend a little with a hand blender. Blanch the cleaned broccoli in boiling water. Arrange the gratinated salmon fillets with the sauce on plates. Garnish with broccoli and lemon slices.