While making the pictures for this lab, the one thing that initially stood out to me was that once I took a picture using a/ the fill, the shadows casted by the cookies became less prevalent, but it seemed as if the overall color of the cookies was being drained out as the light was being reflected back at them. I had an issue with the white balance, but using the auto-adjust in Lightroom helped turn the blue-ish hued paper back into the white that it’s originally supposed to me.
Try shooting with the Lightroom app as you can set the white balance.