Preheat oven to 350 degrees.
In a medium bowl, combine flour, brewer's yeast, flaxseed, baking soda, and salt.
In a mixer, beat butter, brown sugar, and granulated sugar until creamy. Scrape down bowl with a rubber spatula as needed.
Beat in egg and vanilla.
Gradually beat in flour mixture until blended.
With a large spoon, stir in raisins, oats, and M&Ms.
Roll dough into tablespoon-sized balls and place 2 inches apart on a cookie sheet.
Bake 13 to 15 minutes until the tops of the cookies are golden.
Transfer cookies to a wire rack to cool.