In a bowl, add whole wheat flour, baking powder, baking soda and salt. Fit the balloon whisk and whisk at speed 1 for 1- seconds.
In another bowl, take sugar, add grated orange zest and rub between your fingers till the sugar gets moist, changes color and becomes aromatic. Remove 1 tbsp and set aside separately to sprinkle on top.
To this add yogurt or curd, vanilla or almond extract and run the mixer at speed 1 for 10 seconds.
Add the flour mixture and once again run the mixer at speed 1 till the mixture becomes thick and there is no dry flour left. You can also use a spatula.
Add the melted butter, run the mixer at speed 1 for 10 to 15 seconds till well incorporated. You can also use a spatula if doing by hand. The batter will be very thick.
Transfer to the greased skillet or pan. Level and smooth the top using a spatula.
Sprinkle sliced almonds evenly on top and then sprinkle the 1 tbsp sugar that you kept aside evenly on top (more around the sides and less over the center).
Place the skillet in the preheated oven and bake at 180 C for 45 mins. If using a regular cake tin, then bake for 30 to 35 mins.
Check doneness by inserting a toothpick in the middle and if it comes out clean without batter sticking to it, the cake is done.
Remove the skillet or pan and let it cool for 10 mins. Insert a sharp knife and run it along the edges to loosen up the cake.
Once the cake is completely cooled, remove on to a plate.
Slice and serve this eggless orange cake as such or with a scoop of ice cream or clotted cream.