How to make
Beat the eggs along with the sugar in a water bath at a temperature not exceeding 37 degrees. If you do not have a kitchen thermometer, you can beat them in the standard way, just when slightly heated, the fluffy cream is more thick and does not lose its volume.
Melt the butter with the white chocolate over low heat or in a water bath. Carefully mix the egg and chocolate mixture.
Sift the flour with the baking powder and mix with a spatula with smooth movements, until it is completely absorbed. Finally, add the chopped nuts.
Pour the brownie mixture into a suitable baking pan (I used a 7x10″ /17x26 cm/ rectangular one), covered with baking paper or greased and put it in a preheated oven at 360°F (180°C). Do not forget to preheat it, because a cake batter with baking powder should not be left long and should be baked straight away.
Bake the blondie for 20 minutes and then leave it to cool.
Melt the dark chocolate with the butter and milk. If it is too thick, add milk.
Fill the chocolate in a piping bag with a thin, smooth tip and prick it inside of the cake and inject the dark chocolate in places.
You can do this after you cut it and then instead of piercing the top do it from the side. With the rest of the chocolate mixture, make beautiful stripes on the surface of the chocolate blondies.
Enjoy this unique chocolate cake!