Before your start: Make the flax egg by combing ground flaxseed with lukewarm water and set aside to thicken.
Preheat oven to 350°F and line a baking sheet with a silicone baking mat or parchment paper. Set aside.
Melt vegan butter in the microwave in a medium-sized bowl. Add the brown sugar and granulated sugar and using rubber spatula mix until smooth - about 5 minutes. Mix in vanilla extract and flax egg until incorporated.
Mix the all-purpose flour, baking soda, and salt into the butter/sugar mixture until a dough forms.
Fold in the chopped chocolate.
Divide the dough into four and roll into balls. Place on the prepared baking sheet with 2-inches between each.
Bake for 11-12 minutes or until golden brown.
fresh from the oven sprinkle each cookie with a little kosher salt. Let cool on the baking pan for 5-10 minutes before transferring to a cooling rack to cool completely.