Hard boil the eggs. Quarter the apple unpeeled and cut into thin slices. Clean the spring onions and cut into very fine rings.
Mix the salad mayonnaise, yoghurt and curry powder. Season to taste with salt, pepper and sugar. Mix in the apple, light green and white parts of the spring onion. Peel the eggs and quarter or even sixth and fold in. Serve sprinkled with the leftover green spring onion rings.
If you leave the egg salad in the refrigerator for half an hour, it is perfect.