Location: The Dalimil Inn
Petitioner: Matej, Master Baker
Unlocked: Complete Letting Off Steam
Reward: 1 Gobin Coin, 10 Renown, 800 gil
In order to unlock this side quest you need to progress far enough into the main story to reach Out of the Shadow. The majority of Out of the Shadow consists of three sub-quests, all called Letting Off Steam. Complete the three parts of Letting Off Steam, unlock the next area, and visit it once to gain access to all of the side content, including Use Your Loaf.
Travel to the Dalimil Inn and walk along the central path through the town. There's a man named Matej on your right, and he runs a bakery - only his apprentice has run off somewhere. Matej can't leave his shop unattended, and he asks Clive to look for his apprentice. He suggests checking near Drake's Fang.
Fast Travel to the Jaw, to the south of the Dalimil Inn. You may never have seen it before, but there's a stretch of desert down this way. (Watch out for the Nine of Knives in the middle of the path, if you haven't beaten him already.) In the northeast you'll find a ridge, and Dusan, the apprentice, is sitting here and looking at the remains of Drake's Fang. He's despondant, and needs cheering up. You'll receive three options for what Clive can say, though the only difference in the end is the dialogue.
Travel back to the Dalimil Inn and speak to Matej again to complete the quest and earn your reward.