Peel and wash the potatoes and cut them into thin slices. Boil eggs in boiling water for about 10 minutes until hard. Peel onions and cut them into thin slices. Mix potatoes, onions, oil and paprika in a bowl, season with salt and pepper.
Place the potatoes on a baking tray lined with baking paper and bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 25-30 minutes. Remove the eggs, rinse in cold water and peel.
Wash the oregano and dab dry. Put 4 stems aside for garnishing. Pluck the remaining oregano leaves from the stems. Turn potatoes once and sprinkle with oregano leaves. Meanwhile wash parsley and chives and dab dry.
Pluck parsley from the stalks and cut into strips. Cut chives into rings. Dice gherkin finely. Chop eggs and mix with yoghurt, salad cream, parsley, cucumber and chives.
Season to taste with salt and pepper. Garnish potatoes with oregano and add tartar sauce.