Place eggs and water (to the 1L fill level) into mixing bowl and start Egg Boiler /Medium hard. Discard cooking liquid. Run eggs under cold water to cease cooking and set aside to cool. Then peel and cut into halves.
Place celery into mixing bowl and chop 2 sec/speed 5.
Add reserved eggs, yoghurt, mayonnaise, mustard, oil and capers, then mix 10 sec/reverse/speed 2.5. Place in a bowl and set aside. Clean and dry mixing bowl.
Place beetroot and radishes into mixing bowl and chop 3 sec/speed 5.
Place a layer of spinach on the toasted bread, followed by the beet and radish mixture, then the egg mixture. Sprinkle with finely chopped green onion and season with salt and pepper.