In a small bowl combine the flax meal or chia seeds with the water. Set aside for 5 minutes to thicken.
Preheat the oven to 350℉. Line two baking sheets with parchment or a silpat and set aside.
In a medium sized bowl, cream together the butter and sugars for 2-3 minutes, until light and fluffy. Add the flax or chia mixture and vanilla and beat until incorporated.
Add the flour, baking soda, baking powder, cornstarch, and salt and mix until combined. Add the chocolate chips and mix in by hand until evenly dispersed throughout the dough.
Using a 1-inch cookie scoop, scoop out the dough and drop on the prepared baking sheets leaving about 2 inches between each cookie.
Bake for 7-8 minutes. They will look underdone, but they will continue to cook as they cool and leave you with a nice chewy texture. Let cool on the baking sheet for 2 minutes before transferring to a cooling rack to finish cooling.