For cake: Bring the butter to room temperature and beat it for 10 mins in high speed using an electric beater.
When the butter turns pale, add the powdered sugar and beat for 5 mins until it blends well.
Then add four egg yolks one by one and blend well. Add vanilla extract.
Mix the AP flour, baking powder, baking soda and salt and add it to the butter mix in batches. While adding the flour, the speed of the beater should be switched to minimum. Beat the egg whites separately until stiff peak forms and fold it to the batter.
This batter will be a thick one. However if it looks a bit dry after adding the flour, feel free to add 2 tbsp of milk to loosen the batter.
Now grease two baking pans and divide and pour the batter equally in the pans. Place it in a pre heated oven and bake at 180℃ for 40 mins or until a toothpick inserted comes out clean.
When the cake is done, allow it to cool completely and then refrigerate it for 1 to 2 hours.
Then add the frosting.
For frosting : mix 3 tbsp AP flour, milk, sugar and salt in a saucepan without lumps and switch on the flame. Heat the mixture at low flame until thick.
When thick as a pudding, switch off the flame and cover the mixture with a cling wrap to avoid a white patch forming on top.
When it cools completely, take the electric beater and beat 100gms unsalted butter well in a pan for 5 mins. When butter turns pale, add a tsp of vanilla extract. Then blend in the milk pudding mixture in batches (a tablespoon at a time) and beat well until well incorporated.
The frosting is ready. Apply it on the cakes. You can also put colours to the frosting or pipe it into various shapes using a piping bag.
