In a large bowl, combine the shredded cabbage, grated carrot, and minced onion.
In a separate bowl, whisk together the mayonnaise, sugar, buttermilk, white vinegar, lemon juice, salt, and pepper.
Pour the dressing over the cabbage mixture and toss to combine. Make sure every piece of cabbage is coated in dressing.
Cover the bowl and refrigerate for at least 2 hours, or preferably overnight, to allow the flavors to meld.
Stir well before serving. Enjoy!
Notes
For best results, use a high-quality mayonnaise. Taste and adjust seasonings as needed. You can add a touch more sugar or vinegar to suit your preference.