In a large mixing bowl, cream together the butter and brown sugar until smooth.
Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
In another bowl, combine the flour, flaxseed meal, brewer's yeast, and baking soda. Gradually add to the butter mixture and mix well.
Stir in the oats and chocolate chips.
Drop by rounded tablespoonfuls onto ungreased baking sheets.
Bake for 10-12 minutes or until edges are golden brown. Allow to cool on baking sheets for 5 minutes before transferring to wire racks to cool completely.
Notes:
Store cookies in an airtight container at room temperature for up to a week, or freeze for longer storage.