First of all, prepare the pastry: put all the ingredients in a bowl and work quickly, until you get a homogeneous dough, then wrap it with cling film and let it rest in the fridge for at least 1 hour.
In the meantime, prepare the cream: start whipping the egg whites with salt in a bain marie, when they begin to whisk, add the sugar and continue whipping for about 5 minutes, until you get a swollen, shiny and firm meringue, with the sugar completely dissolved. .
Remove from the water bath and continue to whisk to let it cool.
At this point, stir in the softened butter and vanilla, again with a whisk, and then also the icing sugar.
Color the cream with a few drops of food coloring, mixing well to make it distribute evenly.
Take the dough back, roll it out into a fairly thin sheet and create your rounds, respectively 4.5 cm, 4 cm and 3 cm.
Place the circles on the baking sheet lined with parchment paper (I prefer to put them already in order of size, as they will be combined, so the work afterwards will be faster) and cook for about 10 minutes at 180 ° C, in a preheated convection oven, then leave cool completely.
Assemble the saplings: place one of the large circles of pastry on a tray or serving plate, create a nice layer of cream with a sac-à-poche with a star spout, decorated with sugars.
Repeat with the second floor: cover with the circle of the middle size, create another layer of cream, decorated with the sugars.
Finish with the third floor: place the smallest circle, add a nice sprig of cream (this time make it more pointed) and decorate with sugars and a star on top.
The alberelli biscuits are ready, you just have to serve them.