Clean cabbage, peel carrots, wash both and grate very finely. Onions peel and finely dice. Mix everything with salt, pepper and sugar and knead well with your hands.
Stir mayonnaise, buttermilk, vinegar and lemon juice until smooth and mix with the salad. Mix everything in a large bowl and let it stand for about 1 hour. Season to taste with salt, pepper and sugar.