Preheat the oven to 170 degree Celsius.
Sieve the dry ingredients: Whole wheat flour, oats flour, baking powder, baking soda, salt and cardamom powder 3-4 times.
In a large bowl, add mango puree, olive oil, curd, vanilla extract and brown sugar.
Whisk all the wet ingredients to obtain a smooth mixture.
Fold in the dry mix to get a batter. The batter should be slightly thicker than cake batter. Do not over-mix.
Grease the doughnut pan with some oil. Pour the prepared batter with help of a small spoon or a piping bag.
Insert the prepared doughnut tin into the oven in the middle rack and bake for 15-20 minutes or until the skewer comes clean.
Remove the baked doughnuts from the pan after 5 minutes and let them cool down completely.