Wash the potatoes and boil in water for about 20 minutes. Clean the cucumber and wash well. Clean, peel and wash the carrot. Grate both roughly on a household grater. Stir yoghurt and crème fraîche until smooth.
Fold in cucumber and carrot. Season dip with salt, pepper and sugar. Peel garlic and chop finely. Wash herbs and chop roughly. Drain potatoes. Heat oil in a pan. Fry the potatoes in it, turning them occasionally until golden brown.
Add garlic and sauté briefly. Season with salt, pepper and herbs. Wash the lettuce leaves, drain well and arrange on a plate. Arrange roast potatoes, chicken aspic and some yoghurt-vegetable dip on top.
Serve the rest of the dip separately.