I just found this recipe and it worked like a charm. My wife no longer hates coleslaw!
1 (16 ounce) package coleslaw mix
2 tablespoons minced onion
1/3 cup white sugar
1/2 teaspoon salt
1/8 teaspoon ground black pepper
1/4 cup milk
1/2 cup mayonnaise
1/4 cup buttermilk
1 1/2 tablespoons white wine vinegar
2 1/2 tablespoons lemon juice
Combine the coleslaw and onion in a large bowl.
In a separate bowl, combine the sugar, salt, pepper, milk, mayonnaise, buttermilk, vinegar, lemon juice and mix until smooth. Pour over the coleslaw and onion mixture, stir well and chill for 1 hour.