Heat a small fry pan and add the olive oil, swirling to coat the bottom of the pan.
Add the garlic and saute for 2 minutes or so. The garlic should be fragrant but not brown. Remove from heat and allow to cool for a few minutes.
Scoop the avocado flesh into a deep bowl or the pitcher of a blender. Add the buttermilk and cooled garlic and olive oil mixture.
If using the bowl, blend with an immersion blender until smooth. If using a blender, whirl until smooth.
Add the herbs and spices, if you choose, along with a pinch of salt. Whirl/blend one more time and give it a taste.
Adjust the seasonings to your liking and transfer to a bowl or jar with a tight fitting lid. Refrigerate for an hour or so to let the flavors get better acquainted.
Serve as a dressing on salad, a sandwich spread, a dip for veggies or chips, a topping for chicken, or just lick it off of a spoon.