Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a small bowl, mix the ground flaxseed with water and let it sit for 5 minutes to create a flax egg.
In a medium bowl, whisk together the flour, cocoa powder, baking soda, and salt. Set aside.
In a large bowl, mix the melted coconut oil or vegan butter with the granulated sugar and brown sugar until combined.
Stir in the flax egg, almond milk, and vanilla extract. Mix until smooth.
Gradually add the dry ingredients to the wet mixture, stirring until just combined. Avoid overmixing.
Fold in the vegan chocolate chips.
Scoop tablespoon-sized portions of dough onto the prepared baking sheet, spacing them about 2 inches apart.
Bake for 8–10 minutes, or until the edges are set. The centers will still look slightly soft.
Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.