Grease and dust baking tin and preheat oven to 180 degrees. Measure and keep the walnuts ready. Peel and mash the bananas without any lumps. You could use blender too. In a bowl add the mashed bananas, sugar, oil, vanilla essence. Mix thoroughly till the sugar dissolves. Sieve wheat flour, baking powder, baking soda, pinch of salt and pinch of cinnamon powder directly in the same bowl. Now fold the dry ingredients into the wet ingredients part by part and mix well. Add walnuts & fold again. Pour the batter into a tin.