In a food processor with the S blade attachment, add all the ingredient in this order avocado, tahini, chopped cilantro, lemon juice, crushed garlic, olive oil ,chili flakes and salt.
Process on medium speed until the dip is smooth and no more lumps of avocado appears. You may have to stop the food processor every 30 seconds, scrap down the sides of the bowl with a spatula and repeat until smooth.
Transfer the dip into a large bowl. Refrigerate at least 1 hour to allow the flavors to blend. Drizzle one tablespoon on top of your dip before serving.
Storage: store well in the fridge in an airtight container up to 3 days. The top may get darker as avocado oxidize with air. Simply give a good stir before serving and it will look as green as the first day you made it. This does not alter taste. Tahini replacement: you can replace tahini by nut butter of your choice.