In a large mixing bowl, cream the butter and sugar for about 5 minutes or until creamy and pale. Add the vanilla and beat again. Then add the egg and beat until smooth. Add the peanut butter and beat until combined. In a separate ball, sift the flour, cocoa powder, baking soda and gently whisk together. Then add the dry ingredients to the wet and mix together. Add the rolled oats, M&M's and chocolate chips and stir until combined.
Line cookie sheets with parchment paper. Using a cookie scoop, scoop cookies about 2 inches apart. Bake for 12-15 minuets. Leave the cookies on cookie sheets to cool completely before gently moving to a wire rack. They will be quite fragile until they cool completely