First, prepare the cream mixture by melting the white chocolate in a water bath. Gradually pour in the liquid cream, stirring constantly, but be careful not to boil the mixture. You will get a runny cream, leave it in the refrigerator to set.
For the layers, beat the butter well and add the sugar. Whip until you get a fluffy cream and add the eggs one by one. Next, add the sifted flour with the baking powder and baking soda, stirring by hand with a spatula. Mix the milk with the citrus essence and pour it in portions in parallel with the flour. Mix well to obtain a homogeneous mixture.
Grease and lightly flour 2 trays with a diameter of 10″ (25 cm), put in 1/3 of the mixture in one and 2/3 in the other. Put them to bake for about 35-40 minutes; you will need less time for the thinner layer. Check readiness with a stick.
Allow the baked layers to cool well and divide the thicker one into 2 separate layers. Set aside a part of the hardened cream for covering the cake, add crushed biscuits to the other. Place one layer in an appropriate tray, smear with cream well, place the second layer, cream again, place the third layer and cover the cake with plenty of cream.
Sprinkle the top with chopped walnuts. Put the cake in the refrigerator for several hours before serving.