Yuca flour, also called u0022farinhau0022 or u0022toasted sour manioc flouru0022 is derived from cassava root. Cassava root is native to Brazil. It’s used in many dishes in various forms and flours and is naturally gluten and grain-free. Tapioca and tapioca flours are derived from this root too! u003cbr/u003eu003cbr/u003eFor this specific recipe we'll be using toasted sour manioc flour, which you can find at a Brazilian store, oru003ca href=u0022https://amzn.to/3rIk5fDu0022u003e onlineu003c/au003e. It's a little more difficult to find at conventional western grocery stores, but you can also experiment with using other flours, it just won't be authentic.