Prepare a moka (of 3 servings) of coffee and let it cool down.
Crush the dark chocolate into small peaces (with a knife).
Beat the egg whites until stiff.
In a different bowl whisk the yolks with the sugar, until the mix becomes creamy. Add the mascarpone and keep whisking. Add the teaspoon of marsala and the whites little by little and mix gently, from bottom to top.
Take a biscuit and dip it in the coffee, for less than a second, or it will become too soaked. Place it on a large casserole or oven pan, and continue with the rest of the biscuits until you've covered the bottom of the pan. Cover with a layer of the mascarpone mix. Make layers of mascarpone and biscuits. In the middle sprinkle with the dark chocolate. Finish with a layer of mascarpone mix and sprinkle the powder chocolate.
Keep in the fridge for a couple of hours, if it's eaten the same day, or in the freezer if eaten a different day, but take it out 4-5 hours before eating so that it won't be frozen.