How to Make It
In a food processor, combine the flour, sugar and salt and pulse several times. Add the shortening and pulse until the mixture resembles coarse meal. Add the eggs and milk and pulse until the dough is evenly moistened. Turn the dough out onto a lightly floured work surface and knead a few times until smooth. Form the dough into 2 disks, 1 slightly larger than the other. Wrap the disks in plastic and refrigerate for 30 minutes or for up to 3 days.
In a large bowl, mix the eggs with the mozzarella, ricotta, ham, 1 teaspoon of salt and 1/2 teaspoon of pepper.
Preheat the oven to 375°. Between sheets of plastic wrap or on a lightly floured work surface, roll out the larger disk of dough to a 13-inch round and line a 10-by-1 1/2-inch pie plate with it. Patch any cracks. Spoon in the filling. Roll out the remaining dough to an 11-inch round. Brush the pastry rim with water and set the round on top. Press the edges together to seal. Trim the overhanging dough and crimp decoratively. Make 3 small slashes in the top crust and brush lightly with the egg wash. Bake the pizza rustica for 40 to 45 minutes, or until the pastry is golden on top. Cover with foil if the crust browns too quickly. Let cool for 1 hour before serving.