In a large bowl, sift together the dry ingredients - wheat flour, all-purpose flour, powdered sugar, baking powder, baking soda, and cinnamon powder. Keep aside.
In another bowl, mix together the wet ingredients - apple puree, melted butter, and milk. Whisk well.
Gently fold in the dry ingredients in batches to form a smooth batter.
Add in a tablespoon of oil and mix well.
In the meantime, preheat the oven at 180°C.
Line the baking tin with parchment paper. Make sure the parchment paper on the sides is at least three-inch high so that the risen cake does not overflow.
Pour in the batter and tap a few times so that the batter settles down.
Bake the cake at 180°C for 30-35 minutes. Check with a toothpick if the cake is cooked. Move it to a rack and allow it to cool completely.
Remove to a plate. Dust with sugar. The Eggless Apple Cake is ready to serve.