Boil the potatoes until done and let them cool. In the meantime, prepare the sauce. Combine the cream cheese, curry powder and Marne Coarse Mustard in a large bowl and mix everything well. Cut the ham, pearl onions and gherkins into more or less equal parts and add them to the mixture in the bowl. Finally, cut the potatoes into pieces and add them to the bowl as well. Mix everything together carefully. Please note: if you mix too hard or for too long, the salad will be too fine and smooth. Let it rest so that the flavors can blend well. The salad is at its best when you let it rest in the refrigerator overnight.