普洱 is Pu'er (the English spelling is patterned after the Mandarin pronunciation), the city in Yunnan associated with the tea. And 茶 is tea, so 普洱茶 is Pu'er tea.
About This Dish
Pu'er tea is a dark, fully fermented tea grown in the Yunnan province of China. It is post-fermented, where the leaves age even after drying.
Trivia
The Dragonball Z character Puar is named after Pu'er tea.