- Preheat the oven to 350°F (180℃). Line a large baking sheet with parchment paper. Set aside.  
- Make the flax egg: In a small bowl, combine the ground flax seeds and water. Let it thicken as you prepare the rest of the recipe. 
- In a medium bowl, add the vegan butter, cane sugar and brown sugar. Beat together until creamy. 
- Add the vanilla extract and flax egg to the wet mixture and stir to combine. 
- In the same bowl, add the cornstarch, flour, baking soda and salt. Stir until combined. Avoid overmixing. You can use a different bowl for these dry ingredients before mixing them to the wet ingredients if preferred. Stir in the chocolate chips. 
- Roll the dough into 12 small balls and place them on the baking sheet, keeping some distance between each cookie.  
- Bake for 10-13 minutes or until lightly golden. Let them cool for 5 minutes, then transfer them to a cooling rack.