WoWDB

Do not eat this right away! You need it for the achievement  'Tis the Season. If you already ate it and need another in order to earn the achievement, you can create a ticket and ask a GM to send you another - but keep in mind that the wait time for support tickets at this time of year is measured in days.

Edit: From BlizzardCS (verified Blizzard Customer Service account) on Wowhead -

Hey guys! We have some awesome news for this year's Winter Veil. We recently received a letter from Graccu himself, explaining us some changes he decided to introduce this year to make everyone's life easier. We thought you would enjoy the read:

"Graccu sad of making people sad. Graccu want people happy. Graccu want people enjoy Fruitcake. Graccu make more this year. Graccu now extend distribution chain to include retail market through Smokeywood Pastures. Graccu put Fruitcake in Stolen Presents too. Graccu want people happy. Graccu out."

So this year, for all your joy and happiness,  Graccu's Mince Meat Fruitcake will be much easier to obtain. You can buy it from Kaymard Copperpinch or Macey Jinglepocket for 99 gold 99 copper. Additionally, you'll also be able to obtain one Graccu's Minced Meat Fruitcake each day from  Stolen Present!

Happy Winter Veil to all of you! :)

The fruitcake is inside the  Smokywood Pastures Sampler mailed to your character once you've completed Treats for Greatfather Winter / Treats for Great-father Winter.