ウィリアム・スミス・クラーク
is served on top of cooked rice to make curry rice. Curry sauce is made by frying together curry powder, flour, and oil, along with other ingredients, to make roux; the roux is then added to stewed meat and vegetables, and then simmered until thickened. Pressure cooking can be used as well. Adding potatoes to curry sauce was introduced by William S. Clark of the Sapporo Agricultural College, due to rice shortages at the time.