Mountains of tiramisu
This is an authentic Roman cafe-pastry shop far from the more theatrical and touristy places of the city. The tiramisu is great! You can get it in chocolate, banana, strawberry, pineapple...and, of course, coffee. It's located right after you leave the city walls near the Archbasilica of St. John Lateran and I assure you that, even if you're not crazy about tiramisu (as was my case), this will make you see the dessert through different eyes. Still not convinced? Well, there is also an interminable variety of sweets, cakes, and ice cream, so dieters be warned!