Mustard Seed Imprints

Ingredients: 1 lb. of cold boiled potatoes, 1 small beetroot, some spring onions, olives, 4 tablespoonfuls of vinegar, 2 of salad oil, a little tarragon vinegar, salt, pepper, minced parsley. Instructions: Cut the potatoes in small pieces, put these into a salad bowl, cut up the onions and olives, and add them to the potatoes. [...]