Preheat oven to 350°F and spray two baking sheets with cooking spray or line with parchment or Silpat and set aside.
Make flax eggs by whisking together ground flaxseed with water. Set aside.
In a medium bowl, mix together oats, oat flour, brewer's yeast, baking soda, baking powder, cinnamon and salt. Set aside.
In a large mixing bowl mix together oil, sugar, flaxseed eggs and vanilla until smooth.
Add dry ingredients into the bowl with the wet ingredients and stir until just combined.
Gently stir in chocolate chips.
Using a spoon or cookie scoop, drop cookie dough by rounded tablespoonfuls about 2 inches apart on baking sheets. Press each cookie down with a fork a bit.
Bake for 10 minutes, or until golden brown. The cookies may seem a little soft, but do not over bake or they’ll get too crisp. Remove from oven and let cool on sheet for about 5 minutes or until they start to harden up a bit. At this point you can transfer the cookies to a wire rack to cool completely.
Store cookies in an airtight container in the fridge for up to 10 days or in the freezer for up to 3 months.