For cake: Preheat the oven at 180 deg. Seive maida, baking powder, baking soda twice and keep aside. (Dry ingredients)
In a bowl add condensed milk, yogurt, milk, and melted butter and whisk well. It might look curdle not to worry. (Wet ingredients)
Add maida (dry ingredients) batch by batch to wet ingredients make sure there is no lumps.
In a greased cake tin pour the batter and tap twice to remove any air bubbles.
Bake the cake for 25-30 mins. Insert a tooth pick to check if it's full cooked.
Let the cake cool down and invert the cake from tin.
Caramel sauce : Take sugar add water in a sauce pan and let it boil in a medium flame.
Don't add any spoon. Use the handle of the vessel and try to shake the pan to mix sugar and water.
Once sugar gets caramelized you will get wonderful aroma. The colour will change to golden brown.
Remove from stove and immediately add in fresh cream and at once used balloon whisk and start mixing up well.
Add vanilla essence butter and salt to caramel sauce. Allow it to cool and store in refrigerator.
Buttercream frosting :
In a wide bowl take butter and start to cream it pale colour using electric beater.
Seive icing sugar without any lumps formed. Add icing sugar to butter and continue beating in low speed.
Add caramel sauce and icing sugar batch by batch to the cream.
Finally add vanilla essence to caramel buttercream.
Now cut the cake into two half and start applying buttercream in between layers.
Add the buttercream to the sides and finally finish it on the top of the cake.
Add caramel sauce on the top of the cake and drizzle on sides.