Mix the ground flaxseed and water in a small bowl and set aside to make your flax egg.
In a large bowl using a handheld mixer or a stand mixer with the paddle attachment, beat the softened vegan butter for a minute until creamy. Now add in the brown sugar and mix for 1-2 minutes, until fluffy.
Add the vanilla and the flax egg and mix in.
Next, stop the mixer and add 1 cup of the flour and sprinkle the cornstarch, baking soda and salt on top of the flour. Turn the mixer on low speed, and mix until just combined.
Add the other 1/2 cup of flour and mix until crumbles form, then use your hands to form a large ball of dough. The dough should be easy to handle, not too wet or dry. If the dough is too wet to handle, add a few tablespoons more flour at a time. If the dough is too wet, your cookies will be totally flat. If the dough is too dry, add a tablespoon or two of almond milk.
Add in the chocolate chips to incorporate, either by hand or with a spoon until they are evenly distributed.
Cover the bowl tightly with plastic wrap and refrigerate/chill for at least 30 minutes, and up to 1 day. Sometimes I skip the chilling part, and the cookies turn out fine, just not as thick.
Remove the cookie dough from the fridge and let sit on the counter for about 15 minutes. Preheat the oven to 350 degrees F and line two cookie sheets with parchment paper or silicone mats.
Roll the dough into balls, about 1-2 tablespoons each. Bake for about 10 minutes, until they are barely golden around the edges. Do not over bake! They will be puffy and lightly colored. Let cool on the cookie sheet for 5 minutes, then transfer to a cooling rack. The cookies will firm up as they cool, and become the most perfect chewy cookies ever! Enjoy.
Cookies should stay fresh for 4-5 days, if they last that long.
TIP: Freeze cookie dough balls to have on hand to make just a few cookies at a time! Simply cook for 1-2 minutes more, no need to thaw.
May substitute coconut oil for the vegan butter if desired. Just make sure it's not melted, you want it to be semi-firm.
If you don't like salt in your cookies or your vegan butter is very salty already, you may omit the salt.
Recipe adapted from https://sallysbakingaddiction.com/2012/08/06/the-chocolate-chip-cookie/.