Bignè di San Giuseppe are such a special treat that you'll only find them at one moment in the year in Rome (and that's probably a good thing).
Although you can bake this pastry (as traditional French style choux pastries are usually made), make no mistake: They won't be bignè di San Giuseppe unless they're fried. The result is a wonderfully soft, fluffy pastry that feels surprisingly light in terms of texture and consistency. Paired with a thick pastry cream and a light dusting of confectioners' sugar, it's not overly sweet and makes just the thing to eat with your morning coffee for a special breakfast treat.
The pastry cream recipe is edited slightly from my cookbook, Florentine (Hardie Grant Books), and will make about 680 grams. It's a little more than you need for this recipe, but leftover pastry cream is never a bad thing! The bigne recipe is based on a traditional proportional recipe for choux pastry. I used eggs from my family's own backyard chickens: They weigh about 57 grams each and the yolks are bright orange! Here is a handy video (in Italian) that lets you see what each step of the batter mixture and frying should look like. —Emiko
Whisk the yolks and sugar together until pale and creamy. Stir in the cornstarch. Transfer to a saucepan and place over low heat. Add the milk, little by little, stirring between each addition. Add the vanilla. Stir continuously with a whisk or wooden spoon until smooth and thick, about 10 minutes. Look for a consistency like mayonnaise (it will firm up further when chilled). Do not let it boil. Remove from the heat.
Cool the cream quickly by transferring to a mixing bowl (or something shallow like a baking dish) set over an ice water bath. Cover with plastic wrap, making sure the plastic is on the surface of the pastry so it doesn't develop a skin. Once the cream is a bit cooler, chill in the refrigerator to cool completely before using.
For the bignè:
Combine water, butter, and sugar in a saucepan and bring to the boil. Turn the heat down to medium-low and add the flour, stirring continuously until you see the mixture become very smooth and come away from the sides and bottom of the pan. It should look like a smooth ball of dough. Remove from the heat.
Stir the eggs directly into the saucepan (or you can transfer this mixture to a stand mixer, then add the eggs) and whisk by hand or with electric beaters for several minutes, or until the mixture becomes smooth and sticky (you should see it go from looking lumpy like scrambled eggs to becoming very smooth, thick, and quite sticky). Let rest, covered, for 30 minutes.
When you are ready to cook the bignè, set a medium saucepan filled with enough vegetable oil so that they the bignè can float over low heat. Test the temperature of the oil by dropping in a small bit of batter: It should should sizzle lightly around the edges with many tiny bubbles.
Scoop a heaped tablespoon of the batter, then use another tablespoon to help scrape the mixture into a ball or a blob and drop it carefully into hot oil. Cook a few at a time, but not too many at once because these will puff up to double their size, at least!
Cook the bignè slowly over low heat, turning them occasionally, for about 10 minutes, or until they are golden and very puffed, turning the heat up every so slightly towards the end. During frying they should split partially and begin growing further—this gives them their characteristic "bumpy" look. If they brown too quickly too early, the oil is too hot and you need to turn the heat down. When done, leave to drain on kitchen paper and continue frying the rest of the batter. Let the bignè cool completely.
Make a small incision at the bottom of the bigne. With a piping bag, pipe the chilled pastry cream into each bignè until full. Dust with confectioners' sugar before serving.
Naturally, these are best when made on the day, but if time is working against you, you can successfully make these bignè the night before and fill them the next day for serving. The pastry cream keeps well for several days in the refrigerator.
The Australian-Japanese cookbook author has lived in Florence (where a visit to a cheese farm once inspired her to start a food blog) for over 10 years with her Tuscan sommelier husband and two kids. Her third cookbook, Tortellini at Midnight, is out now.