Peel, wash and coarsely grate the carrot. Wash and dry cucumber and also grate it coarsely. Peel onion and cut into rings. Wash lettuce leaves and dab dry. Mix yoghurt, buttermilk and lemon juice and season to taste with salt, pepper and sugar. Chop dill finely and stir into the sauce. Arrange the salad ingredients on plates and serve garnished with dill flags as desired