Start by making the creams, so they have time to cool while you're making the layers. Make the milk cream by putting the milk to heat on the stove, then add the sugar.
Next, add the mixed together flour and starch. Stir nonstop until ready. Remove from the stove and leave to cool completely. Once it is, add the butter and beat well with a mixer to obtain a fluffy cream.
To make the caramel, put the sugar and walnuts in a casserole on the stove until caramelized. Pour the mixture into a pre-buttered plate and leave to cool. Then unstick it and blend in a blender.
To make the sugar syrup, put the water and sugar to boil in a pot. Leave to boil for 10 min.
For the white topping, heat the liquid cream a little, add the sugar and butter and then the crumbled white chocolate.
Carefully add the whites to the yolks and stir. To this mixture, add the flour, baking powder, cocoa mixture and stir. Put it in an oiled tray and bake in a preheated 356°F (180 °C) oven until ready. Let the cake layer cool and then divide it into 3.
Then start assembling the cake. Place the 1st layer and syrup it. Pour milk cream on top and the crumbled caramel. This time around I didn't put caramel between the layers. Place the 2nd layer on top, syrup it again and smear with the cream mixture, then caramel.
Place the 3rd layer, syrup it and smear the entire cake with cream mixture all over. Decorate with caramel on the sides. On top, make rosettes using a pastry bag. Smear with the white chocolate topping in the middle.