In a food processor, shred or mince cabbage, carrots and onions very fine, to size of a grain of rice.
In a bowl, mix mayo, sugar, milk, sour cream, lemon juice, white vinegar, cayenne, and pepper until smooth. Add sauce to the well mixed and well distributed cabbage, carrots and onion. Stir and incorporate well.
Place in refrigerator and allow at least 2 hours before serving or preferably overnight.