Sieve whole wheat flour 6 times, then add baking powder, baking soda and cinnamon powder and again sieve it for 2 more times and keep aside.
Mash the ripe bananas with a fork, add vanilla extract and keep aside.
In another mixing bowl take both the sugars, yogurt and vegetable oil mix it with a whisk, then add mashed bananas to it and again mix well.
Now add the flour to the vet ingredients and fold in everything nicely, then add warm milk and walnuts and mix the batter well.
Pour the batter in a lined baking tin and bake it in a preheated oven over 170°c for 40-45 minutes. After 40 minutes check the cake by inserting a toothpick, if it comes out clean remove the cake from the oven and cool it over a wire rack for 30 minutes before unmoulding. Cool the cake for 2-3 hours before slicing it.
