Combine together all the ingredients using the buttermilk to get a soft dough. The dough consistency should be such that you can easily make small balls with it and roll them into rounds. Cover the dough and let it sit overnight at room temperature. When preparing the buns, take out the dough and add the mashed bananas to it. If you are not using the bananas, skip the above step and continue below. Knead the dough well. Make small balls out of the dough, enough to roll each one into approximately 4 inch diameter rounds. Deep fry in oil on high-to-medium heat till crispy and golden brown. Drain. Eat when hot. These buns will keep for about 1-2 days and need not be refridgerated.