Place a mixing bowl beneath a sieve. Add 1 cup all purpose flour (maida) and 1/2 teaspoon baking powder in the seive. If using unsalted butter, then you can add a light pinch of salt in the flour. Sift once.
Sprinkle 1 teaspoon vanilla extract or 1/2 teaspoon vanilla essence all over the flour. You can also add vanilla extract later after mixing the batter.
In a pan, take 1/4 cup salted butter, 1/2 cup condensed milk, 3 tablespoons sugar and 1/3 cup water. I used organic unrefined cane sugar. You can also use regular sugar.
Place the pan on stove top and heat this mixture on a low flame.
Stir with a spatula so that the butter melts. Mix everything very well with the spatula.
Let this mixture come to a boil on a low flame.
When this mixture comes to a boil, then immediately add it in the flour mixture.
With a wired whisk begin to mix with a light pressure, so that over mixing does not happen.
While mixing you will come to know if the batter is going to be thick or too thick. The batter in this recipe is of medium consistency – neither thick nor thin.
Depending on the quality of flour, you may need to add less or more water. If the batter becomes thick, then do add ¼ cup more hot water. So do keep some hot water handy.
Whisk to a smooth batter, but don't over do the mixing. If there are small tiny lumps in the batter, then its fine.
Now pour the batter in the pan. Gently shake the pan or tap the sides.