Preheat the oven to 180°C and prepare the 8 inch square baking tin or you can also use 2 loaf tins by brushing it with some oil and lining with a parchment/baking paper.
In a bowl sift in together all purpose flour, whole wheat flour, baking powder, baking soda and a pinch of salt and keep it aside.
Now add the caster sugar/granulated sugar along with the cardamom seeds in a mixer grinder and ground it together until powder.
In a large bowl add the butter and sugar together and beat it with a hand whisk until light and fluffy and pale.
Now add in the eggs, one at a time and beating after each addition of egg until incorporated. Do not over beat.
Add the flour mixture along with the vanilla extract and with a spatula fold everything together. (If you think the batter is too dry add a tsp of milk and fold it lightly.)
Now slowly pour the thick batter in the prepared baking tin and smoothen it slowly with the spatula.
Bake it in the oven for 22-30 minutes. Check it after 22 minutes by inserting a tooth pick. When you Insert a toothpick to it will come out clean.
Remove from the oven and let it cool.
Preheat the oven to 150°c.
Line a large rectangular baking pan with parchment paper.
Now cut the cake into 3/4 inch strips.
Place the cake rusk on the baking tin and bake in preheated oven for 12-15 minutes on each side.
Remove from the oven. Let it cool complete on a cooling rack.
Store it in an airtight container for 2 weeks. Enjoy!!