Preheat the oven to 180 C
Combine dry ingredients in flour sifter and sift into an ungreased 8x8 square or a 9-inch round baking pan. You can also use a 9-inch cast-iron skillet.
Poke three holes into the flour mixture. In the first hole, pour the vinegar. In the second hole, pour the vanilla. In the third hole, pour the oil.
Then pour one cup of water into the pan and mix very well.
Stir in the diced banana and nuts - shake pan to level off and sprinkle some powdered cinnamon.
Place in the oven and bake for 30 minutes or till done.
Cut in squares and serve warm.