How is Cassava Flour Made and Used? 

Native to South America, cassava is heavily relied upon as an energy source in Sub-Saharan Africa. Becoming a popular gluten-free flour alternative and thickener, cassava flour (aka tapioca flour) is made from the starchy root of the yuca plant. It is not refined; the whole root is used to make flour. Use caution if attempting to make your own cassava flour and never eat raw cassava: It contains a compound that produces cyanide, which is eliminated when cooked.

Source: How is Cassava Flour Made and Used? – Food & Nutrition Magazine