Wash herbs, shake dry. Pluck parsley leaves from the stalks and chop them. Cut the chives into fine rolls, except for a little to garnish. Peel onion. Cut one half into rings, dice the rest.
Mix quark, mineral water, onion cubes and herbs. Season to taste with salt, pepper and sugar. Wash, clean and slice the tomato. Cut the fat edge off the ham. Cover bread with cottage cheese, tomato and ham.
Garnish with onion and chives and sprinkle with pepper.