In a mixing bowl, add the mayonnaise and sour cream.
Whisk them together until they are well combined and smooth.
Gently pour in the buttermilk while whisking continuously.
This helps avoid any lumps and ensures a consistent texture.
Add garlic powder, onion powder, salt, and black pepper to the mixture.
Mix thoroughly to integrate all the flavors.
Stir in the fresh chopped dill and parsley.
These herbs add an essential freshness to the dressing.
Transfer the dressing into a jar or airtight container.
Let it chill in the refrigerator for at least two hours to allow flavors to meld.