Preheat the oven to 350 degrees F. In a small bowl mix the flax seed and water and let it sit for 3-5 minutes.
In a large bowl beat butter, sugar, and brown sugar until well combined. Add the eggs and mix well. Add the flaxseed mix and vanilla extract and beat well.
In another bowl sift together flour, brewers yeast, baking soda, and salt. Add the dry ingredients to the butter mixture and mix well. Stir in the oats and chocolate chips.
Scoop onto a baking sheet in balls that are about the size of a golf ball (can make them smaller or bigger). Press down a bit with a spoon.
Place into the oven and bake for 12 minutes. Let sit for a couple of minutes and then remove from the baking sheet.