Dragon Slippers by Jessica Day George

Orphaned Creel is taken in by poor relatives, including her silly aunt who hatches a plan to get the girl captured by a dragon so that a knight will rescue her and marry her, thus lifting the rest of the family out of poverty. However, the dragon wants no part of this arrangement, and in order to avoid the trouble of fighting a knight, agrees to let Creel select one item from his hoard (he collects shoes) and encourages her in her ambitions to become a seamstress in the royal city. Unbeknownst to Creel, the simple blue slippers she selects have a history that dates back centuries and the power to control dragons. When the slippers fall into the wrong hands, Creel may be the only one able to turn the tide of the war that threatens her country.