Directions

1. Mix the dry ingredients together in a bowl. Chop the cold butter into small pieces and pulse together in a food processor until it resembles breadcrumbs. Add the egg and lemon zest and knead just until the mixture comes together. If you find it a bit dry, add some cold water, a tablespoon at a time until it forms a dough; if it's too wet, add a bit of flour. Cover in plastic wrap and rest at least 30 minutes or overnight.
2. For the filling:
3. If you're using uncooked wheat berries, then you first need to cook them by soaking them in water for 3 days (change the water twice a day), then draining and cooking in a large pot of at least 4 cups of fresh water. Simmer for 1 ½ hours without stirring, until soft. Drain and reserve until needed (this will keep well in an air tight container the fridge for 1 week) then carry on to the next step. If using pearl barley as a substitute, leave the uncooked barley to soak in a large bowl of fresh water overnight, then the next day cook it in plenty of water for 30 minutes or until soft. Drain then follow the rest of the recipe.
4. Place the cooked wheat berries in a saucepan over medium heat with the butter, milk and lemon zest. Bring to a boil gently, stirring occasionaly until it becomes very thick and creamy like oatmeal, about 15 minutes. Let cool until needed.
5. In a bowl, beat the eggs and extra yolks with the ricotta, sugar, vanilla, cinnamon and orange blossom water until creamy. Leave this mixture to rest several hours (better if overnight) in the fridge.
6. Fold the cooled wheat berry cream and the rested ricotta mixture together with the finely chopped candied citron.
7. Roll out about two thirds of the pastry and place in a 10 inch (25 centimeter) greased springform tin. Cut off any overhang and add to the remaining pastry, roll out again and with a pastry crimper wheel, cut long strips about ¾ an inch wide.
8. Fill the pastry base with the ricotta mixture and even out the borders of the pastry to the level of the mixture. Lay the long pastry strips gently across the top to form a a criss-cross diamond pattern (not square), pressing the strips on the edge of the pastry very gently. If desired, you can brush the lattice gently with some egg wash to make it shiny.
9. Bake the pastiera for 1 hour at 390ºF (200ºC) until the pastry is golden and the pastiera is amber-brown on top.
10. Allow to cool completely inside the springform pan before removing or chilling. Ideally serve the pastiera the next day (remove it from the fridge at least 30 minutes before eating to take away some of the chill) with some powdered sugar sifted over the top. Store any leftovers in the fridge.