Making ugali is simple but takes a strong arm. The cook boils water in a pot, slowly stirs in maize flour, and then keeps stirring as it thickens into a firm dough. After a few minutes, the cook tips it out onto a plate, where it cools into a soft, sliceable block.
Most Tanzanian families eat ugali with their hands. You break off a small piece from the block, roll it gently in your palm to make a little scoop, and use it to pick up the side dishes. The two most common partners are a meat dish (often nyama choma - grilled meat) and a green vegetable like sukuma wiki or mchicha (a kind of spinach).
Almost every country in the world has a 'staple' food - the everyday thing that the whole family grew up eating. In Italy it might be pasta. In Mexico it is tortillas. In Japan, rice. In Tanzania, it is ugali. The side dishes change with the season; the ugali is almost always there.
Maize, the plant ugali is made from, didn't always grow in Tanzania. It first grew in the Americas thousands of years ago and slowly travelled around the world. Today it is the most important food crop across much of East Africa - so important that 'maize' and 'food' are almost the same word in many Tanzanian families' minds.