Take a baking tin grease the butter and dust flour n tap to remove excess flour. Sift the flour, baking powder and baking soda thrice and keep it aside. Now take the milk in a bowl and add vinegar to it and keep it aside for 2mins.
Once it cuddles add the oil, sugar and beat it well. Now add the flour mixture and mix it well in cut and fold method. Add blueberries and finely chopped rosemary leaves n mix well.
Now pour this batter into the prepared cake tin and bake in a preheated oven at 180 degree celsius for 20-25 mins. After the cake is baked cool it down & demould . Then mix the yoghurt n icing sugar n beat well .
Spread the icing sugar over the cake n decorate with a rosemary sprig.