Mix sugar, salt, pepper, mayonnaise, milk, buttermilk, celery seed, hot pepper sauce, and minced onion together; let sit for 15 minutes.
Mix cabbage, carrots, and dressing together in a large bowl.
Let sit for at least 1 hour up to 24 hours.
Serve.
Notes: Buttermilk can be replaced by milk with a little bit of vinegar in it, or sour cream, yogurt, or whey milk. Dry minced onions can be replaced by 1/2 cup fresh chopped onion or green onion.