Preheat oven to 350 degrees and line a cookie sheet with parchment paper or lightly oil.
To make flax egg, stir together flax meal and water in a small bowl. Set aside for 10 minutes or until a gel is formed.
Add mashed banana and mashed avocado to a food processor and blend until creamy. Add flax egg, cocoa powder, baking soda and coconut sugar and blend until well combined.
Transfer to a bowl and stir in chocolate chunks.
Using a tablespoon, drop dough onto lined or greased cookie sheet.
Bake on 350 degrees for 15-18 minutes until lightly crispy on the edges. Let cool and enjoy :)
Store in an air-tight container in the refrigerator.
These cookies are a bit on the sticky side, so make sure to line or grease a cookie sheet :)