In a measuring cup take 1 cup maida and remove 2 tbsp from it .Add 2 tbsp of cornflour to the maida in the cup. So in total we have 1 cup of dry flour.
In large bowl sieve maida , corn flour ,baking soda and baking powder twice to ensure even mixing.
In another bowl take yogurt, oil ,sugar,salt and vinegar and mix nicely so that sugar dissolves.
Preheat oven at 180c for about 10 mins .
Now slowly start adding dry flour to the curd mix little by little.Beat well with light hands in 1 direction until creamy and thick.
Add choco chips and vanilla essence and give a quick mix.
Line the muffin tray with muffin liners.
Evenly fill the muffin cup with spoonful of batter till 3/4 of the muffin cup.Once the batter is in the pan, tap the muffin tray on a countertop to release any large air bubbles in the batter.Top it with few more choco chips if you want.
Line the muffin tray in the centre of the oven and bake in preheated oven at 180c for 20-25 mins or till a fork inserted into the muffins comes out clean.Just 5 minutes before completion of baking ,remove the cake and brush it with little milk.This gives a golden crust.
Allow the muffins to cool down in wirerack.
Enjoy the muffins as such or top it and decorate with your choice of topping..This stays good for 3-4 days without refrigeration.
Don't fill the muffin liners more than 3/ 4 th else it will overflow while baking.
Addition of vinegar makes the cake more fluffy .Vinegar reacts with baking soda and start the chemical reaction needed to produce carbon dioxide and give those batters a lift as they bake. In the end result you will not be able to make out weird taste or smell of vinegar.
You can use normal granulated sugar or powdered sugar.
Use curd at room temperature only.
Do not reduce oil n curd quantity. That will the cake hard as its eggless.
Once the batter is ready don't allow it to sit for sometime. You have to bake immediately.
As a variation you can add orange rind/ lemon rind/ blue berrys etc for a different flavor.