uncommon divination metamagic sorcerer 

Bloodline imperial

Cast [>] verbal

You call upon your blood's knowledge of the ancients to extend your magic. If your next action is to Cast a Spell with a duration of 1 minute on a single target, and the spell isn't of the highest spell level you can cast, the spell instead lasts 10 minutes. You can have only one active spell at a time extended in this way.

Core Rulebook, page 404.