Peel, wash and halve the potatoes, boil them in salted water and cook for about 25 minutes. In the meantime clean, wash and cut leek into fine rings. Wash fish, dab dry (remove bones if necessary) and cut into 8 slices.
Sprinkle with lemon juice. Then season with salt. Drain the potatoes, let them evaporate a little and press them through a potato ricer. Heat milk and 25 g butter in a small pot. Mix egg and horseradish.
Stir the milk and egg radish into the potatoes, sift the flour on top and mix well. Season to taste with salt and nutmeg. Pour into a piping bag with a large star-shaped spout. Place the salmon slices on a baking tray lined with baking paper.
Spray the mashed potatoes spirally onto the salmon slices and bake in the preheated oven (electric cooker: 200 °C/ gas: level 3) for 20-25 minutes. In the meantime whisk the egg yolk and cream. Clean and wash the tomatoes and carve them crosswise as you like, cut them in half or cut off the lid.
Season with salt and pepper. Sprinkle with cheese and spread 10 g butter on top. Heat 40 g butter in a wide saucepan, add leek, cover and cook over low heat for 12-14 minutes. Then season with salt and pepper.
Halfway through the baking time, place the tomatoes on the baking tray and cook to the end. Brush the mashed potatoes with whisked egg yolk. Serve salmon, tomatoes, arranged as desired on lemon slices and garnished with chervil and oregano.
Add the leek vegetables.