Suterare Shiro Mahoutsukai no Koucha Seikatsu

During a quest to subdue a golden dragon, a white mage named Amalia is double-crossed by her party, abandoning her with mortal injuries. While she accepts her fate, the dragon takes pity on Amalia's helpless situation and heals her in exchange for a favor: to help him observe human life. The dragon then takes the form of a child, using "Yuugo" as an alias. After accepting Yuugo's request, Amalia soon realizes that a decade has passed since the day she was betrayed. Despite being overwhelmed by a surge of emotions, Amalia resolves to move forward, starting a new life with Yuugo as her foster son. Eventually, Yuugo shows an interest in the culture of tea, and as someone adept in brewing the exquisite drink, Amalia helps him explore the diverse tastes the beverage has to offer.