To make the mayonnaise, in a medium-sized bowl add Egg (1).
Whisk until yolk becomes slightly thickened and light yellow in color.
Add Lemon Juice (1 teaspoon) and Dijon Mustard (1 teaspoon), vigorously whisk until combined.
Very gradually add a few drops of Olive Oil (1/4 cup) to the egg mixture.
Continue to add small drops at a time, creating an emulsified and thickened sauce.
Whisk until you see the mixture lighten in color and start to thicken.
Once 1/4 cup of oil has been added and is visibly thickened, add Lemon Juice (1 teaspoon) to the sauce and mix to combine.
Continue to gradually drizzle and whisk in another Olive Oil (1/4 cup).
Add the last Lemon Juice (1 teaspoon), whisk to combine.
Slowly drizzle and whisk the remainder of the Olive Oil (1/2 cup) into the mayonnaise. This should yield about 1 cup of mayonnaise.
In a blender, add mayonnaise, Avocado (1), Italian Flat-Leaf Parsley (1 cup), Fresh Chives (1 tablespoon), Scallion (2 tablespoon), Tarragon (2 tablespoon), Garlic (1 teaspoon), Anchovy Fillets (2), Water (1/4 cup), Apple Cider Vinegar (2 tablespoon), and Kosher Salt (1/2 teaspoon).
On medium speed, blend until smooth, about 1 minute.
Taste green goddess dressing and more salt and Ground Black Pepper (to taste) as desired.