The Apothecary Diaries 05 (manga) by Natsu Hyuuga

After breaking a "curse" on the imperial heirs, a palace servant with training in herbal medicine is promoted up the ranks to food taster...and right into the thick of palace intrigue in this lushly illustrated historical mystery series!

Forced to the leave the Inner Palace, Maomao finds herself in the employ of none other than Jinshi, the seemingly ever-present thorn in her side! Immune to his charms, Maomao sets about learning the ways of life in the Outer Palace, where government officials and military officers go about the daily business of running the country.

Far from being fearful of her new surroundings, however, Maomao has her insatiable curiosity piqued by the soldier-occupied eastern wing, where she's been forbidden to go but where it seems further mysteries await...