In a bowl, mash blue cheese and greek yogurt together with a fork, breaking up any large chunks until well combined.
Add in vinegar, lemon juice, Worcestershire, onion powder, garlic powder, salt and pepper.
Stir in buttermilk a little at a time until desired consistency. If you like your dressing thinner, add more buttermilk.
Let sit for at least 30 minutes before serving to let flavors come together. Check for seasoning and serve. Store leftovers in an airtight container in the fridge for up to five days.
Notes
If using buttermilk instead of buttermilk powder, omit the water and use ¼ cup of buttermilk.