2: ...and grind them to a fine powder. Repeat if necessary.
3: Pour the powder into a salad bowl, add 200 g Mascarpone, 1 tablespoon icing sugar, 80 g cold coffee and possibly 1 tablespoon Marsala.
4: Mix by hand...
5: ...until you obtain a homogeneous paste.
6: Cut the dough into 90-100g pieces.
7: Roll the dough into a ball between your hands...
8: ...and place them as you go on a baking sheet. Place in the fridge, covered with cling film.
9: A few minutes before serving, roll the balls in cocoa powder...
10: ...and tap to remove excess.
11: Do this for each ball, then serve within half an hour, otherwise the cocoa will moisten and turn a very dark brown, far less appetizing.
Remarks
You can replace the sponge cookies with boudoirs. This is a recipe that can easily be made into filled balls: As you roll them, insert a small piece of fruit purée or jam (for example) in the middle, which you've hardened in the freezer in small heaps.