Begin by gathering all your ingredients on a clean countertop.
Slice the ripe avocado in half, remove the pit, and scoop the flesh into your blender or food processor.
Peel the garlic cloves and add them to the blender. Next, slice the green onion and toss it in as well.
Pour in the buttermilk and add the fresh lime juice.
Chop the cilantro and, if using, the fresh dill. Add both to the blender.
Blend all the ingredients together until the mixture is smooth and creamy.
Taste your dressing and season with salt and pepper according to your preference.
If you're not using the dressing immediately, transfer it to an airtight container and store it in the refrigerator.
