Kasha

Kasha is a cereal commonly eaten in Eastern Europe. In English, kasha generally refers to buckwheat groats, but in Slavic Europe, it refers to porridge in general and can be made from buckwheat or any cereal wheat, barley, oats, millet and rye. At least a thousand years old, kasha is one of the oldest known dishes in Eastern European Slavic cuisine.

Kasha in Supervolcano
After the Yellowstone Supervolcano eruption, weather patterns were disrupted making the climate cooler with shorter growing seasons. Farmers starter growing buckwheat (also known as kasha) which was better adapted to the changed conditions.