I have been making Tiramisu and Mascarpone and their variations for years now and until I started living in Italy have always (for some reason) considered them 2 different desserts. Until you go to some restaurants here asking for Tiramisu and they serve you Mascarpone and when you complain they tell you that it's the same thing.
This is probably like one of those French grammar exercices that the Teenager had been doing for the CNED : quel est le champs lexical du mascarpone?
When I gave it a very quick thought, a Tiramisu is always made with mascarpone. Even when I called it Summer Tiramisu or Mascarpone Millefeuille, it's basically made with mascarpone (the cheese). It's a simple but very rich cream cheese usually made from boiled buffalo milk "curdled" by tartaric acid (preferably), lemon juice or vinegar. And if you don't have mascarpone, ricotta could eventually be a good substitute.
When you go to a restaurant and order Mascarpone, it's a dessert made with the cheese. And there are 2-3 basic ways to make it : 1) with egg yolks, egg whites and mascarpone; 2) with egg yolks, whipped cream and mascarpone; 3) with whipped cream and mascarpone.
Method 1 yields a lighter mascarpone (the dessert). Method 2 is denser, richer. Method 3 is what I do often when I'm not sure how fresh the eggs are.
Last evening I made a batch of Mascarpone using method 1 for dessert since I had fresh organic eggs. But for Friday's French dinner party, I will use method 2 as we are used to eating a denser dessert.
Mascarpone (the dessert) :
250g Mascarpone (the cheese)
3 Eggs (yolks and whites separated)
Beat the egg yolks with the sugar till thick and creamy. Add the mascarpone and continue to beat till creamy.
Crush the dark chocolate into rough bits with a rolling pin or in a mortar. Add to the mascarpone mixture.
In another bowl, whisk the egg whites till stiff. Fold gently into the mascarpone mixture.
I filled a bowl halfway with some of the finished mascarpone and topped it with a few raspberries and amaretti (a dry bitter and sweet almond biscuit loved by the Italians). Then filled the bowl with more mascarpone. Chill for a few hours if not overnight before serving.
If you like your amaretti hard, just leave it as it is. If you like it softer, you may wish to dip it in a bit of coffee or fruit juice before adding it to the mascarpone. The amaretti imparts a rather strong almond flavour to your mascarpone.