This is a wonderfully simple, crowd pleasing crostata. Cherry jam (preferably made with wild sour cherries) spread over a base of soft, crumbly, almost cake-like crust, and covered with a lightly-sweetened ricotta filling. A lattice top usually garnishes the crostata, but it's just as pretty without.
It's one of the consistent dessert items on Roman trattoria menus, yet the tradition itself was born in the Roman Ghetto. The traditional Roman Jewish ricotta and jam crostata made famous by the bakery Boccione, in via del Portico d'Ottavia, right in the heart of the Ghetto, is unique in the world. The recipe, a secret, is fiercely guarded and notoriously difficult to replicate.
The Boccione crostata's unique features include a rounded and a burnt-until-blackened top sans crust. It's not necessarily pretty, but the bitterness of the burnt top contrasts with the sweetness of the jam (quite like in a crème brulee) to create a balanced tart, much sought-after by those in the know of where to find Rome's best pastries.
They say this ricotta crostata is an ancient recipe and at one time was a way for Jewish vendors to sell – illegally – cheese, by hiding it under a pie crust. The older recipes included honey and candied fruit but over the last couple of centuries this ricotta crostata has become a more common dessert found all over the city of Rome.
Instead of jam, you could also use plump, fresh pitted sour cherries. A common variation on this crostata is chocolate chips stirred through the ricotta in place of the jam.
Traditionally sheep's milk ricotta is used and is preferable for its rich flavour and usually firmer texture. If using cow's milk ricotta and you find it's quite “wet” rather than firm, pour it into a sieve lined with a few layers of muslin (or a clean linen tea towel), set it over a bowl and let it drain overnight.
The recipe was inspired by an Italian cookbook on Roman cuisine called La Cucina di Roma e del Lazio and the pastry crust is adapted from one of Pellegrino Artusi's recipes for “pasta frolla” in his 1891 cookbook, Science in the Kitchen and the Art of Eating Well. It works wonderfully: soft, crumbly and should be cooked so it's on the blond side and remains soft and cake-like. —Emiko
For the pastry crust:
(250 grams) of flour
(100 grams) of fine sugar
stick (½ cup or 125 grams) of cold butter, diced
For the pastry crust, combine the flour and sugar in a bowl. Add the butter and rub into the flour until the mixture appears crumbly (alternatively, pulse together in a food processor). Add the lemon zest, the egg and yolk and combine until the pastry just comes together into a smooth ball. Rest the pastry in the fridge for 30 minutes or overnight.
In the meantime, prepare the ricotta filling by beating the ricotta, eggs and sugar until smooth and creamy.
When the dough has rested, take about two-thirds of the dough and, on a floured surface, roll this to about 1/8 inch thickness to cover a 26cm or 10 inch pie dish. Trim the edges.
Spread the jam over the pastry dough. Pour the ricotta mixture over this and smooth out the surface.
With the remaining third of the pastry dough, roll on a well floured surface to 1/8 inch thickness and cut into strips about ½ inch wide, if you want a lattice top. Layer the strips in a criss-cross pattern over the top and secure the ends on the edges of the pastry with a dab of water or the leftover egg white. If doing this without a top, save this dough for another use in the freezer.
Bake the crostata at 350ºF for 25 minutes or until lightly golden and the centre of the crostata feels springy.