For the tartar, remove the seeds from the melon and cut into slices. Cut the flesh from the skin and dice finely. Dice the ham. Clean and wash radishes and cut into fine sticks. Rinse cress and cut from the bed.
For the vinaigrette, whisk vinegar, salt, pepper and 1 pinch of sugar. Fold in the oil. Stir in the radish and cress.
Place four starter rings (each 8 cm Ø; 4 cm high) on one plate each. First layer diced melon and then diced ham. Spread radish and cress vinaigrette on top.