When cooked over a wood fire or on a conventional stove, hard porridge (known locally as sadza, nshima, ugali, tô, fufu, banku, nigoni, putupap, and maize meal among other names) is cooked by putting cornmeal into boiling water. To prevent burning, the contents of the pot have to be stirred very well. Then the porridge is put on a big flat plate and cut into pieces to be served with vegetables.
In a solar cooker of the box- or panel-type, it is prepared in a different way: you just put the corn flour into the cold water (1.5 parts water, 1 part cornmeal), stir well, and then put the covered pot into the cooker. There is no stirring necessary since the heat is very even and there is no concentrated heat coming from a flame under the pot. Another advantage of this method is that the pot almost never needs any cleaning afterwards.
Jill Miller-Cranko of Zimbabwe reports: We have found that the cornmeal "sadza" does need to be stirred once during cooking. We advise to let it cook for 2 hours, open the pot and stir, and return to cook for a further 1 - 2 hours (depending on the quantity being cooked, and the strength of the sun). If left to cook for 3 - 4 hours without stirring it seems to go hard. But this may only apply to us when we are using CooKits.