Whisk the 3 tbsp. buttermilk, 2 tbsp. mayonnaise, and 2 tbsp. sour cream together in a medium bowl.
Stir in the dried herbs (1 tsp. dried minced onion, 1 tsp. dried parsley flakes, ½ tsp. dried chives, ¼ tsp. each of onion powder, garlic powder, and dried dill).
Stir in a pinch each of salt and pepper, taste, and add more of either if preferred. For a thinner dressing, stir in more buttermilk (1 tsp. at a time) until the dressing is the consistency you like.
Cover and chill for an hour in the refrigerator for the best flavor, or serve immediately!
