Add the flour, powdered sugar, salt, lemon zest, and cold butter cut into cubes to a stand mixer. Mix for a few seconds until the mixture is crumbly, like sand. Quickly add the egg and mix in the stand mixer until the dough pulls away from the sides of the bowl. Place the dough in a covered bowl and refrigerate for at least 30 minutes.

Cook the farro in plenty of boiling water (it took me about 25 minutes). Drain and return it to the pot with the butter, milk, salt, and lemon zest. Cook over low heat for 15 minutes, stirring, until the farro becomes creamy and absorbs all the milk. Transfer to a bowl, remove the lemon zest, and let cool.

In a bowl, mix the ricotta with the sugar until smooth. Cut the dried apricots into small pieces. Add the ricotta, apricots, and chopped dark chocolate to the farro, mixing until well combined.

Take the pastry dough from the fridge and divide it into two parts (2/3 and 1/3). Take the larger portion and roll it out between two lightly floured sheets of parchment paper to a thickness of about 1/4 inch (5 mm), forming a round shape. Use this to line a 8-inch (20 cm) round springform pan, pressing it up the sides. Trim any excess dough from the top edge and prick the bottom with a fork.

Fill the crust with the prepared filling. Roll out the remaining dough with a rolling pin to a 1/4 inch (5 mm) thickness. Use a pastry wheel to cut strips and arrange them in a lattice pattern over the top of the pastiera.

Bake in a conventional oven at 350°F (180°C) for 40-45 minutes, until the top is golden brown. Remove from the oven and let the pastiera cool completely before removing from the pan and serving with a dusting of powdered sugar.