Cassava

Cut off both ends, score and remove the thick brown peel and the pinkish layer beneath it, then cut the root into chunks. Boil in plenty of water until completely tender, usually for 20–30 minutes, and discard the cooking water; never eat cassava raw.

A fork should pass through the chunks easily, and the centre should be soft rather than chalky or firm. Remove the tough, stringy core before serving if it has not already come away during cooking.

For chips or fries, boil peeled chunks until just tender, drain and let them dry well before frying in hot oil until golden. This gives a fluffy centre and crisp outside; frying raw cassava alone does not make it a safe substitute for thorough cooking.

Boiled cassava is served with stews and grilled fish, while fried cassava chips are a popular side. Grated cassava is used in Brazilian-style pão de queijo and farofa, and its starch is made into tapioca pearls and cassava flour.

Choose firm roots without soft spots, mould or a shrivelled skin. Fresh cassava deteriorates quickly: keep it cool and use it promptly; once peeled, refrigerate it submerged in water and use within a couple of days.

They come from the same root, but they are not the same food: tapioca is the starch extracted from cassava. Cassava is eaten as a root vegetable, while tapioca is used in pearls, puddings and as a thickener.

Cassava has more carbohydrate per 100 g: 30 g, compared with 17.5 g in potato. Its energy is 128 kcal per 100 g, while potato has 80.6 kcal.