Make the pasta frolla: Work the butter with the flour and salt on a counter until they are thoroughly combined. Pour in the sugar. Knead it in gently with your hands. The dough should begin to come together. Add the vanilla extract and egg yolks. Work the ingredients in gently with your fingertips until a dough forms; add a touch of flour if the dough is sticking to your hands or to the counter. Avoid over-working the dough or it will be tough and dry once it is baked.

Gather the dough into a ball; cut into 2 equal pieces. Pat each piece into a flat disk and wrap in plastic. Refrigerate for 30 minutes or up to 1 day; this will make rolling the dough out easier later.

Make the pastry cream: Whisk the egg yolks, flour, and sugar in a bowl. Heat the milk and vanilla extract in a saucepan until they are nearly boiling; pour slowly into the egg mixture, whisking all the while to prevent curdling. Return the mixture to the saucepan; cook over medium heat until thick without letting it come to a boil, stirring with a wooden spoon once in a while. Cool to room temperature.

Make the Grano filling: Combine 12 cups water, salted as you would for pasta, and Grano in a pot. Bring to a boil, then reduce heat to medium. Simmer, stirring frequently, until Grano is tender but still chewy, about 30-35 minutes. Drain well and cool to room temperature. Process the Grano to a smooth paste with the ricotta in a food processor; a blender will not give the same creamy results.

Turn the processed Grano and ricotta mixture out into a bowl and fold in the sugar. Add the cooled pastry cream and fold it into the processed Grano.

Stir the candied lemon zest, egg yolk, and whole eggs; fold the ingredients together until they are smooth and thoroughly mixed.

Assemble the pie: Preheat the oven to 375°F. Unwrap the dough and dust it on both sides with flour. Roll out both disks of dough into two 16" circles on a lightly floured counter.

Line a generously buttered 10" cake pan with one circle; trim the excess dough with a sharp paring knife. Spoon in the filling; smooth the top. Cut the remaining circle into 12" long strips.

Make a lattice pattern for the pastiera using the dough strips, overlapping them on top of the filling (lay half of the strips over the filling in one direction and the remaining strips in the other direction.).

Bake the pastiera for 25 to 30 minutes, or until the top is lightly browned and the crust is crisp to the touch. Cool the pastiera to room temperature and serve it as a sweet snack or dessert.

Adapted from recipe in La Cucina Italiana, February 29, 2000.