Bring a large pot of salted water to a boil. Add the cassava pieces and cook, uncovered, for about five minutes or until the cassava has softened slightly. Drain and let cool. When the cassava is cool enough to handle, cut into bite-size chunks.

Heat a thick layer of oil in a large skillet set over medium-high heat. Add the cassava chunks; sprinkle generously with salt, pepper and rosemary. Cook, stirring occasionally, for eight to 10 minutes or until slightly browned. Serve warm.