In English, kasha () is a porridge usually made from buckwheat, a pseudocereal. In the Slavic languages, kasha means porridge. In some varieties of Central and Eastern European cuisine, kasha can apply to any kind of cooked grain. It can be baked but most often is boiled, either in water or milk, but the word can also refer to the grain before preparation, which corresponds to the definition of 'groats'.
The word kasha was borrowed from Russian kásha and first appears in English-language sources in 1808.
The English-language usage of kasha, which refers primarily to buckwheat, probably originated with Jewish immigrants, as did the form kashi (literally translated as "porridges").
The word kasha is used in Belarus (), the Czech Republic (), Lithuania (), Poland (), Romania and Moldova (), Russia (), Slovakia (), Slovenia (), Kazakhstan, and Ukraine ().
As an Ashkenazi-Jewish comfort food, kasha is often served with onions and brown gravy on top of farfalle, known as kasha varnishkes. Kasha is a popular filling for knishes, and is sometimes included in matzah-ball soup.
In Polish, cooked buckwheat groats are referred to as . can apply to many kinds of groats: millet (), barley (), pearl barley (), oats (), as well as porridge made from farina (). Bulgur can also be referred to as a type of kasza in Polish ().
As Polish blood sausage is prepared with buckwheat, barley or rice, it is called kaszanka (kasha sausage).
Annual per capita consumption of groats in Poland was approximately per year in 2013.
The largest gross buckwheat consumption per capita is in Russia, with per year, followed by Ukraine, with per year. Buckwheat comprises 20% of all cereal consumption in Russia.
In Russian, buckwheat is referred to formally as (), or colloquially as (), which gave rise to the Yiddish words gretshkes/greytshkelach and retshkes/reytshkelach.
Kasha is one of the Russian traditional dishes. Together with shchi it used to constitute staple foods for poorer people. This fact is commemorated in the Russian saying, "" (), which literally translates as "shchi and kasha are our food".
Butter is often eaten with most kasha recipes, hence another Russian saying: "" (), which translates to "you cannot spoil kasha with butter".