Sift the flour, baking powder, powdered sugar and salt. Keep the dry ingredients aside.
In another bowl, mash the bananas. I got 1/2 cup mashed banana from 4 small bananas.
Add vegetable oil and milk to the mashed bananas and whisk well. You can use hand mixer for mixing.
Add cashewnut pieces and mix.
Pre-heat the oven for 5 minutes at 175C in convection mode.
Line the muffin tray with cupcake liners or paper cups and fill them up to ¾ th with the prepared batter. Leave some space as the muffins will rise. Gently tap the muffin tray. Bake the whole wheat banana muffins for 30 minutes.
To check if the muffin is baked, pierce a toothpick at the centre of the whole wheat muffin. If the toothpick comes out clean, then it is baked properly. Else bake it further for 5 more minutes.