Preheat oven at 180 C deg firstly. (15 mins)
Secondly, measure all purpose flour and take out 3 tablespoon from it. Then add 3 tablespoon corn flour to it. Basically we are taking out 3 tablespoon all purpose flour and replacing it with corn flour.
Sieve all purpose flour and corn flour twice to ensure even mixing.
In a mixing bowl, mix well yogurt (curd) and sugar to dissolve it.
Add baking powder and baking soda (sodium bicarbonate) and mix well. Set aside for 2 minutes.
The mix will become slightly frothy with small bubbles. Now mix in vanilla and oil.
Then add 1 tablespoon of the flour at a time until you finish all the flour to get the batter.
Mix chocolate chip with 2 teaspoon of flour to coat it and add it to the batter, give a gentle mix with a spatula. (You can use the same flour from your mixing bowl)
Line a muffin tray with muffin liners and spoon the batter ¾th in each muffin liner.
Top with few more chocolate chips if you like.
Bake for 18-20 minutes or until the toothpick inserted comes out clean.
Carefully take out from the muffin tray and cool down over a wire rack.