Zynga’s ChefVille leads our list of the fastest growing Facebook applications by monthly active users this week with 2,141 percent gain that pushed the game past 12 million MAU.

Zynga seems to have put its marketing weight behind Chefville rather than The Ville, which had been a top gainer for several weeks. Now The Ville is the No. 1 app on Facebook overall, but has started to see a decline in users. Last week we noticed that Zynga was promoting Chefville with Facebook’s new search ads, Sponsored Results. Zynga’s Bubble Safari was No. 8 this week, CastleVille was No. 9, Ruby Blast was No. 14 and Zynga Bingo was No. 17.

Titles on our list gained the most MAU of any apps on the platform, growing from between 220,000 and 11.56 million MAU, based on our AppData tracking service.

Top Gainers This Week

Name MAU Gain Gain % 1.  ChefVille 12,100,000 +11,560,000 + 2,141% 2.  Washington Post Social Reader 8,000,000 +2,200,000 + 38% 3.  Yahoo! Social Bar 40,800,000 +2,100,000 + 5% 4.  SongPop 16,700,000 +900,000 + 6% 5.  Instagram 28,300,000 +800,000 + 3% 6.  Scribd 21,700,000 +600,000 + 3% 7.  Zoosk 15,200,000 +600,000 + 4% 8.  Bubble Safari 31,400,000 +500,000 + 2% 9.  CastleVille 16,000,000 +500,000 + 3% 10.  Pinterest 16,800,000 +500,000 + 3% 11.  Dragon City 11,000,000 +400,000 + 4% 12.  schoolFeed 16,800,000 +400,000 + 2% 13.  Causes 3,200,000 +400,000 + 14% 14.  Ruby Blast 3,200,000 +300,000 + 10% 15.  Keek 1,500,000 +300,000 + 25% 16.  Pedido de contato 6,700,000 +300,000 + 5% 17.  Zynga Bingo 7,500,000 +300,000 + 4% 18.  BranchOut 2,900,000 +300,000 + 12% 19.  Samsung Mobile 20,300,000 +300,000 + 2% 20.  Rotfltube 770,000 +220,000 + 40%

All data in this post comes from our traffic tracking service, AppData. Stay tuned for our look at the top weekly gainers by daily active users on Wednesday, and the top emerging apps on Friday.