This quest is given by Mooshga at the West Freeport Gates ( -474.36, -45.97, -346.61 ), after you complete the Seafood Surprise quest.
You must mine 5 iron clusters in the Commonlands. This requires a mining skill of 20+. If your mining skill is not 20+ you can raise it by mining in the low level dungeons around Freeport, such as the Graveyard.
Bring them to Mooshga for some coin, experience, and either some Mooshga Mush or the recipe to make it.