1/2 cup mayonnaise
1/3 cup sugar or splenda
1/4 cup milk
1/4 cup buttermilk or sour cream
2 Tablespoons lemon juice
2 Tablespoons white vinegar
1/2 teaspoon onion salt
1/8 teaspoon celery seed
1/4 teaspoon black pepper
…
Mix together, add to prepackaged coleslaw mix.