You are required to gather 4x Wild Mustard to combine with 4x Rhino Dogs using the provided Empty Picnic Basket to complete this quest.
The Wild Mustard can be found in the grassy areas throughout Dalaran:
* Krasus’ Landing (70, 44) in Eastern Dalaran
* Runeweavers Square (49, 46) in Central Dalaran
* The grassy areas surrounding The Violet Citadel (36, 49) in Western Dalaran
You must now combine 4x Rhino Meat into Rhino Dogs and use the Empty Picnic Basket to combine everything together to create the Mustard Dog Basket!.
Once you have the Mustard Dog Basket!, make your way to Krasus’ Landing (70, 44) in Eastern Dalaran to hand your quest in to Archmage Pentarus.