In a small bowl or shaker bottle, whisk mayonnaise, sour cream, and buttermilk until creamy. Stir in finely diced dill, garlic powder, onion powder, sugar, parsley, salt, and pepper.
Add more seasonings according to taste.
Chill for at least 30 minutes. 2 hours is ideal to give time for dressing to thicken.
Drizzle on your favorite salad or use as a dip for vegetables.