I saw this on our recent cruise on the Gem. I didn’t partake as the Filet came with sweet potato mousseline which was a hard no from me. I did wonder if I could get fries maybe if I asked nicely, but the fries aboard the Gem, whether in MDR, Cagneys or Buffet were horrible. So there wasn’t an option that was going to make it worthwhile for me. I will experiment with it next time as the specialty dining experience was a bit average last time.