This is a very substantial soup, or a very good breakfast or lunch dish. For best results all the ingredients used should be fresh, but if you live in a place where sweetcorn is seasonal or does not grow at all, then by all means use canned or frozen corn kernels. If pumpkins are not in season, any yellow-coloured squash can be substituted. But traditionally, in the Minahasa region of Sulawesi, tinutuan has to be made with cassava. In the West, cassava is obtainable from Asian grocers.