Sieve Wholewheat flour, baking powder, soda and salt all together 4 times atleast.
Now mash banana , vanilla essence and add oil and curd and mix well.
Make powder of palm sugar and add in the banana and curd mixture.
At this point put the oven on preheat at 180 degrees.
Now gradually say 3 tbsp at a time mix flour in the banana and curd wet mixture and fold it gradually mixing all of the flour.
If it becomes difficult to folk add couple of tbsp of milk and then add chopped walnuts. Do not over mix it,
Grease a pan, here I took a loaf pan and then add the batter and lightly tap it. Sprinkle some chopped walnuts too.
Add in over and bake at 180 degrees for 35 mins and then so a knife test. If the knife comes out clean the cake is done otherwise bake for another 5 mins.
Let the cake sit in oven for 10 mins and then take it out to cool down and serve.