Prep: preheat the oven to 325°. Spray or line a baking sheet.
Dry Ingredients: In a medium bowl, whisk together the flour, baking soda, salt, brewer's yeast and ground flax seeds.
Wet Ingredients: In a large bowl, using a standing mixer or hand-held mixer, cream the butter for 1 minute. Add in the brown sugar and sugar and cream for 1-2 minutes. Add in the egg and vanilla and cream for 3-6 minutes or until light and fluffy.
Combine: Add in half of the dry ingredients into the wet ingredients and mix on low until just combined. Add in the rest of the dry ingredients and mix on low until just combined.
Add Ingredients: Add in the oats and chocolate chips into the cookie dough and mix with a large spoon or with the mixer on low.
Drop Cookie Dough: using two spoons or a cookie scoop, place a rounded tablespoon of dough onto the baking sheet.
Bake: Place the baking sheet into the oven and bake for 10-12 minutes or until the edges or just golden brown. Sprinkle with flaky salt, if using, while the cookies are still hot.
Cool: let cool on the baking sheet for 2-3 minutes and then transfer to a cooling rack until cool.
Eat and enjoy!