Crumble the 2 types of chocolate. Place half of the gelatin to swell in a little cold water. Heat 2 cups (0.5 liter) of milk with 3 tablespoons of sugar. Pour in the dissolved 1 1/2 tablespoons of starch in 2/3 cup (150 ml) of liquid cream and a little milk to the already boiling milk and stir for a minute or two.
Add a 1/2 ampule of vanilla and the gelatin. Let it cook until dissolved and remove from the heat. Add and mix the crumbled dark chocolate + 2 tablespoons of sweet cocoa. Distribute the chocolate cream on the bottom of dessert bowls, but only fill them halfway, in order to have room for the white part.
Put the bowls to solidify for 3 hours in the refrigerator. Similarly use the remaining half of the products to create the white cream, and finally mix with the crushed white chocolate. Once the chocolate cream hardens, pour the white cream into the bowls and let it set again.