blend potato flour with wheat flour, the pan di spagna will be softer
put sugar into a great bowl
add two complete eggs to the sugar. Use the albumen only of other 4
add salt for a well spongy dough
whisk the batter with electric egg whisk. Artusi suggests 30 minutes when using a hand egg whisk
you can save 10 minutes and whisk for 20 minutes if using electric whisks, but do not whisk for less than 20 minutes
the batter will be ready as soon as pale and dense as in the picture on the left
the dough is ready
now add a pinch of sugar and salt and whisk also the albumens
mix the cocoa with flours
add the flours with cocoa to the dough, a little at time
stir well the dough, it will become very dense
add the whisked albumens, one spoon at time
blend by stirring gently from top to down
spread the dough onto the baking pan
make the dough as thick as required. It can be less or more flat.
pre heat the oven at 300 F (150 C) and bake for 45 minutes
do not open during baking or the cake will droop
Should you use a flat dough 40 minutes can be enough, the thicker is the dough the more time is required, up to 50 minutes. Use a tooth picker for seeing when ready. It must remain dry.
let the pan di spagna become tepid in the oven, for avoiding it to droop
should you use the pan di spagna for making the tronchetto di natale pay attention to cut it while hot, otherwise it will be impossible to roll it
with this dose you can prepare tronchetto di natale for 6/8 persons
