Signor Buontalenti was, in my humble opinion, one of the most inventive cooks of all time. He worked for the aristocratic family de Medici, which surrounded themselves with talent, just like Michelangelo who worked under the Medici's tutelage as well. This recipe is one of those classic and ancient Buontalenti recipes, the zuccotto, a sponge cake dough drowned in liqueur with a center of semifreddo.
Today Zuccotto is defintiely considered a typical Florentine dessert, mostly thanks to Bernardo Buontalenti who played such an important role in the culinary traditions of Florence, however it seems to have spread throughout Italy and has many different versions. The Zuccotto used to have a much more distinguished name, which is rarely used today: The Elmo di Caterina, the helmet of Caterina. It is said that the first ones were formed using a combat helmet from Catherina de Medici's infantry, Zucca meaning "head" in Tuscan dialect.
The original recipe used ricotta cheese mixed with cream, chocolate or candied fruit (citrus) for the semifreddo filling, the outer layer was flavored and colored with bright red alchermes liqueur. Alchermes is notoriously difficult to find outside of Italy so just use Maraschino cherry liqueur or another type of sweet liqueur.

The association of ice cream makers who still make the original Elmo di Caterina
According to an expert from the association of artisanal Florentine ice-cream makers there are only two authentic recipes for zuccotto. One includes fresh cream, Italian meringue, ricotta, cake dough, plus the Alchermes of the Officina Profumo-Farmaceutica di Santa Maria Novella and 70% Amedei Toscano chocolate. The other zuccotto uses candied fruit instead of chocolate but also includes fresh cream, Italian meringue, ricotta, cake dough, the Alchermes of the Officina Profumo-Farmaceutica di Santa Maria Novella.
This recipe I am using today is derived from the original recipe by the association of Elmo di Caterina. After some experimentation, including an attempt with rose petal flavoring, they chose to keep the white colored filling of ricotta and use 70% Tuscan chocolate (Amedei) and a light sponge cake made of oil and flour. Just use the recipe below as a guideline and don't be afraid to make with your adaptation of choice.
When in Florence
When visiting Florence you may like to drop by the following ice cream parlors, all members of the association of Elmo di Catherina to taste their version.
Ballerini - via L. Da Vinci, 2/4 - SignaGelateria Malotti - Piazza Cavour, 14-16 - ScandicciIce Dream in de Via Costetti 7/9 in FlorenceI Gelati del Bondi in Via Nazionale, 61r - FlorenceTrattoria Nerone in Via Faenza, 95/97R - FlorenceTrattoria Cornelius in via Faenza, 62R - FlorenceTrattoria Bondi in Via Nazionale 45/47R - Florence