Preparation Cover wheat berries with cold water in a bowl, then chill, covered, 8 to 12 hours. Drain in a sieve and rinse. Make pastry while wheat berries soak: Sift together 2 1/4cups flour, 1/4 cup sugar, baking powder, and 1/2teaspoon salt. Blend in 1 1/4sticks butter (1/2 cup plus 2 tablespoons) with a pastry blender or your fingertips until mixture resembles coarse meal. Add 2 whole eggs and stir with a fork until a crumbly dough forms. Turn dough out onto a work surface. Divide in half and with heel of your hand smear each piece of dough twice with a forward motion to help distribute fat. Gather dough and form into 2 disks. Chill, wrapped in plastic wrap, until firm, at least 1 hour. Make filling: Bring soaked wheat berries and cold water to a boil in a 2-quart saucepan, then reduce heat and simmer, covered, until wheat berries are tender, about 1 1/2 hours. Add remaining 1/2 teaspoon salt and simmer 5 minutes more. Drain in sieve and rinse under cold water until cool. Drain well. Whisk together 2 yolks and 1/4 cup sugar, then whisk in cornstarch and remaining 3 tablespoons flour until smooth. Bring milk to a boil in a small heavy saucepan, then gradually add hot milk to yolks, whisking. Pour custard into saucepan and bring to a boil over moderately low heat, whisking constantly (custard will get very thick), then boil, whisking, 1 minute. Remove from heat and whisk in vanilla and remaining 1/4 stick (2 tablespoons) butter. Transfer pastry cream to a bowl and chill, its surface covered with wax paper. Beat together ricotta and remaining 1/3 cup sugar with an electric mixer at medium speed until sugar is dissolved, about 3 minutes. Beat in flower water, pastry cream, and remaining 2 yolks, then stir in zest, citron, cinnamon, and wheat berries. Assemble and bake pie: Preheat oven to 350°F. Roll out half of dough into a 13-inch round on a well-floured surface with a floured rolling pin. Fit dough into a 9-inch (24-centimeter) springform pan (dough is very tender and will crack). Press dough against side of pan and patch any cracks. Chill. Lightly beat remaining egg. Roll out remaining dough into a 10-inch round and transfer to a baking sheet. Brush dough with some of egg, then cut into 10 (1-inch) strips with fluted pastry wheel. Spoon filling into chilled pie crust (filling will not reach top of crust). Arrange 5 dough strips vertically on filling (1 inch apart), pressing ends of strips into crust. Arrange remaining 5 strips over them in same manner to form a diagonal lattice. Trim crust 1/2 inch from top of filling, then fold over lattice. Brush edge with some of egg. Bake pie in middle of oven until pastry is golden and filling is puffed and set, about 1 1/2 hours, covering top of pie with foil after 50 minutes to prevent over-browning. Transfer to a rack to cool. Run a thin knife around edge of pie and remove side of pan. Chill pie at least 2 hours. Bring to room temperature before serving.
Preparation Cover wheat berries with cold water in a bowl, then chill, covered, 8 to 12 hours. Drain in a sieve and rinse. Make pastry while wheat berries soak: Sift together 2 1/4cups flour, 1/4 cup sugar, baking powder, and 1/2teaspoon salt. Blend in 1 1/4sticks butter (1/2 cup plus 2 tablespoons) with a pastry blender or your fingertips until mixture resembles coarse meal. Add 2 whole eggs and stir with a fork until a crumbly dough forms. Turn dough out onto a work surface. Divide in half and with heel of your hand smear each piece of dough twice with a forward motion to help distribute fat. Gather dough and form into 2 disks. Chill, wrapped in plastic wrap, until firm, at least 1 hour. Make filling: Bring soaked wheat berries and cold water to a boil in a 2-quart saucepan, then reduce heat and simmer, covered, until wheat berries are tender, about 1 1/2 hours. Add remaining 1/2 teaspoon salt and simmer 5 minutes more. Drain in sieve and rinse under cold water until cool. Drain well. Whisk together 2 yolks and 1/4 cup sugar, then whisk in cornstarch and remaining 3 tablespoons flour until smooth. Bring milk to a boil in a small heavy saucepan, then gradually add hot milk to yolks, whisking. Pour custard into saucepan and bring to a boil over moderately low heat, whisking constantly (custard will get very thick), then boil, whisking, 1 minute. Remove from heat and whisk in vanilla and remaining 1/4 stick (2 tablespoons) butter. Transfer pastry cream to a bowl and chill, its surface covered with wax paper. Beat together ricotta and remaining 1/3 cup sugar with an electric mixer at medium speed until sugar is dissolved, about 3 minutes. Beat in flower water, pastry cream, and remaining 2 yolks, then stir in zest, citron, cinnamon, and wheat berries. Assemble and bake pie: Preheat oven to 350°F. Roll out half of dough into a 13-inch round on a well-floured surface with a floured rolling pin. Fit dough into a 9-inch (24-centimeter) springform pan (dough is very tender and will crack). Press dough against side of pan and patch any cracks. Chill. Lightly beat remaining egg. Roll out remaining dough into a 10-inch round and transfer to a baking sheet. Brush dough with some of egg, then cut into 10 (1-inch) strips with fluted pastry wheel. Spoon filling into chilled pie crust (filling will not reach top of crust). Arrange 5 dough strips vertically on filling (1 inch apart), pressing ends of strips into crust. Arrange remaining 5 strips over them in same manner to form a diagonal lattice. Trim crust 1/2 inch from top of filling, then fold over lattice. Brush edge with some of egg. Bake pie in middle of oven until pastry is golden and filling is puffed and set, about 1 1/2 hours, covering top of pie with foil after 50 minutes to prevent over-browning. Transfer to a rack to cool. Run a thin knife around edge of pie and remove side of pan. Chill pie at least 2 hours. Bring to room temperature before serving.