Chop your leek into thin slices. Transfer to a colander and wash properly. Set aside and let it drain well.
Meanwhile, chop ham and cheese into small bite-size cubes. Next chop apple and pineapple to the desired cube size. Transfer into a big bowl. Drain celeriac from the water and add it to the bowl. Follow with leeks, mayo, and corn.
Give everything a good mix and try for seasoning. Add a pinch of salt and pepper, give a good mix again and let it cool in the fridge for at least 1 hour. The salad will taste much better once it’s cold.
Enjoy by itself or with a side of a nice slice of wholegrain bread with butter.