|Alternative names||Mitha doi (Assamese), Meethi dahi (Hindi), Miṭha dahi (Odia)|
|Place of origin||Bangladesh|
|Region or state||Bogra District|
|Associated national cuisine||India, Bangladesh|
|Main ingredients||Milk, doi (yogurt), sugar, jaggery|
|Variations||Curd of Bogra, Nabadwip-er lal doi|
Mishti doi (Bengali: মিষ্টি দই) or Mitha Dahi (Odia: ମିଠା ଦହି) is a fermented sweet dahi (yogurt) originating from the Bogra District in Bangladesh and is a very popular dessert throughout the country. It is also consumed in the Indian states of Assam, Odisha, Tripura and West Bengal, with similar dishes branching off of it such as the Nabadwip-er lal doi of Kolkata. and in the nation of Bangladesh. It is made with milk and sugar or jaggery. It differs from the plain yogurt because of the technique of preparation. There are many variations of mishti doi according to their popularity.
Mishti doi is prepared by boiling milk until it is slightly thickened, sweetening it with sugar, either gura (brown sugar) or khejur gura (date molasses), and allowing the milk to ferment overnight. Earthenware is always used as the container for making mishti doi because the gradual evaporation of water through its porous walls not only further thickens the yoghurt, but also produces the right temperature for the growth of the culture. Very often the yoghurt is delicately seasoned with a pinch of cardamom for fragrance. Baked yogurt is a similar preparation in the west.
Before the discovery of miracle drugs of typhoid, wellknown alopathic physicians like Dr. B. C. Roy, Col. Denham White and Nilratan Sircar prescribed mishti doi for their patients which helps to accumulate Vitamin Bs.