Vanilla cake: Heat milk and butter together in a microwave or a pan and keep aside to cool to room temperature. Preheat oven to 180°C.
Sift flour, salt, baking powder and keep aside. Grease a baking tin only from the bottom and line with butter paper.
Place a pot with water 1" deep and let it simmer. Place a heat proof bowl over the pot so that it does not touch the water. Add eggs and sugar in the bowl and beat constantly with a whisk.
Once the sugar is dissolved, touch the mixture and it should be slightly warm.
Switch off the flame and beat the egg-sugar mixture with electric beater till it becomes thick and pale. (When you lift the beater from the mixture and draw an 8 pattern, it should remain visible for a few seconds before it disappears).
Add vanilla essence. Fold in the flour in three batches alternating with 2 batches of milk-butter mixture.
Mix till well incorporated. Do not over mix. Transfer to two 8, 7 or 6 inch diameter round cake tin. Bake for 30 minutes or till the skewer inserted in the center comes out clean. Cool the cake completely before assembling.
First you should prepare caramel by heating sugar in a pan. Once it melts completely and turns brown in color keep the flame low and add boiling water. Mix with a spoon and boil for few seconds. Switch off the flame and cool.
Beat at room temperature, butter and Icing sugar together. Beat well until light and fluffy. You can use hand whisk if you want. Add condensed milk and beat well once again. Keep aside.
With another whisk of electric blender beat 5 eggs in a clean bowl. If using the same whisk used for beating butter, make sure its completely clean and free of any grease before beating eggs, else the eggs will not whip up.
Beat the eggs till it doubles in volume. Add half of the beaten eggs to butter, sugar mixture and fold the eggs gently.
To this mixture add sifted flour mixture all at once and fold gently using a spatula till well incorporated. Add remaining beaten eggs and fold gently again.
To this add the caramel sauce prepared earlier and mix everything till well incorporated. Transfer the cake batter to a greased 8" cake tin.
Bake in a preheated oven at 170 degrees for 45 minutes or until skewer inserted in the center comes out clean.
Eggless chocolate cake:
Preheat oven at 180 degrees. Sift flour, cocoa powder, baking soda and baking powder and keep aside. Heat milk, coffee powder, powdered sugar and honey until just warm.
Transfer this milk mixture to a bowl and add oil to it and beat using an egg beater till everything gets well incorporated.
To this add sifted flour and cocoa mixture and beat well till no lumps are visible and everything gets well incorporated.
Transfer the cake batter to a greased cake tin lined with parchment paper or wax paper. Tap the cake tin on the kitchen surface to knock air bubbles out.
Bake in the oven for minutes 55 minutes or until skewer inserted in the center comes out clean.
Making Dulce de leche:
Make Dulce de leche(DDL), one day ahead as it takes time to cook and cool completely. Process explained below:
Peel off the cover of condensed milk, but do not open the can. Place the can in a pressure cooker completely immersed in water.
Close the lid of the pressure cooker and keep on high flame. Once you hear the first whistle, reduce the flame to medium low and cook it for 25 minutes.
(The condensed milk can be cooked in a vessel other than pressure cooker, but will take 3-4 hours and you need to keep on adding water to keep the can completely immersed).
After 25 minutes, switch off the pressure cooker and do not open the lid or place under water for pressure to dissipate. Leave it untouched.
Once the pressure dissipates, Open the lid and take out the can and let it cool completely, else it will explode. This is DDL.
Now you need to make frosting. So when you are making DDL keep butter outside the fridge at room temperature, so that butter is completely softened by next day when you prepare frosting.
For frosting, Beat butter well. Add DDL and beat till everything is well incorporated.
Making the chocolate ganache:
In a dry clean bowl, add chocolate chopped finely. Heat cream in a heavy bottomed sauce pan on medium flame till it starts boiling from sides. Do not over heat the cream.
Switch off the flame and add cream to chocolate, the chocolate should be completely covered in cream. Keep it untouched for a while and then mix slowly using a dry whisk. Keep mixing till you get a smooth lump free ganache.
Assembling the cake:
Cut the top of all cakes to attain a flat surface.
On a plate, place the chocolate cake, put some frosting on top of it. Spread on entire surface.
Place caramel cake on top and apply some frosting again. Now put vanilla layer on top. Cut off the sides of the cake to get even size on sides.
Frost the entire cake in frosting, smooth the side and top using a spatula. Pour ganache on top, allow it to drizzle on sides. Make sure the ganache isn't hot while pouring over the cake else the frosting will melt.
If you keep the cake in fridge it can be hard, so if refrigerating, before serving keep the cake out at room temperature for one hour.