Preheat oven to 350 degrees Fahrenheit. Line 2 baking sheets with parchment paper. In a small bowl, combine ground flaxseeds and 3 tablespoons water. Set aside for 3-5 minutes to gel.
In a medium bowl, combine coconut sugar and a ¼ cup organic cane sugar, followed by peanut butter and vegan butter. Using an electric mixer on medium speed, beat to combine. Then add flax egg, followed by vanilla extract. Mix to combine.
In a second medium bowl, combine almond flour, arrowroot starch, salt, and baking soda. Whisk to evenly combine. Add dry ingredients to wet ingredients and stir until ingredients are incorporated, then use your hands to mix in the remaining dry ingredients. Using your hands is the best way to fully mix the ingredients into a uniform dough. Place dough in refrigerator to chill for at least 30 minutes.
Place remaining ¼ cup organic cane sugar on a plate. Use a tablespoon to scoop out dough. Roll dough in-between your hands into a ball. Place on plate with sugar, roll to coat, then place on prepared baking sheet.
Bake for 10-12 minutes, or until cookies are set on the outside. Remove from oven and wait at least a minute before using your index finger to press down slightly in middle of cookie. Allow cookies to cool on baking sheet for 2-3 minutes then transfer to a wire rack to cool.
Once cookies have completely cooled, place dairy-free chocolate chips in a glass bowl. Microwave at 30-second intervals, stirring after each, until almost all chocolate has melted. Add coconut oil and stir until remaining chocolate chips and coconut oil have melted.
Working quickly, transfer melted chocolate to a plastic sandwich bag. Make a tiny cut in the corner of the bag. Use bag to pipe chocolate into the divets made in the middle of the cookies. Allow chocolate to completely set before serving or storing.
Store in an airtight container at room temperature for up to 3 days.