Preheat the oven to 350 F, line a baking sheet with parchment paper and set aside.
In a high speed food processor, puree the avocado, brown sugar, peanut butter, flax egg, and vanilla until smooth.
Add the cocoa powder, flour, baking soda and salt and pulse until smooth.
Remove the blades, and stir in the chocolate chips using a sturdy spatula or wooden spoon, dough will be thick.
Shape the dough into 15 golf ball sized balls, then place onto the prepared baking sheet and gently flatten into cookie shapes (these cookies do not spread very much).
Bake in the preheated oven 8-10 minutes, or until the cookies are slightly puffed and not wet looking.
Allow to cool 5 minutes on the baking sheet before transferring to a cooling rack to cool completely.