Put sugar in the milk and bring it to a boil on the stove to dissolve the sugar.
Divide the liquid sweetened cream into 3 parts and beat each with a mixer. Put the sour cream and vanilla in the first part. Beat briefly to mix.
Add 2/5 cup (100 grams) of liquid chocolate to the second part and beat it as well. Add the grated white chocolate to the third part and beat it. In a cake form with a ring, arrange a layer of biscotti that you've dipped in the milk syrup.
Cover with all of the first cream. Arrange a second layer of biscotti and cover with the second cream. Add the third layer of biscotti and cover with the third type of cream.
Place in the refrigerator for several hours (overnight is best). Take it out of the ring. Sprinkle with crushed walnuts on the sides.
Decorate the top with strawberries dipped in the remaining heated liquid chocolate.