Make your flax egg by mixing flax and water. Let the "egg" sit refrigerated for 10-30 minutes to set.
In a large bowl mix together your wet ingredients including the flax egg. Pour in dry ingredients except for the chocolate chips and mix. Lastly fold in the chocolate chips.
On a lined sheet pan form 8-10 evenly sized cookies - using about 1 ½ tablespoon worth of dough per cookie. I recommend wetting your hands before forming the cookies as the dough is sticky.
Bake cookies for 10-12 minutes. Let cool and top with additional flaky salt if desired.