Put wheat kernels, butter and salt in a medium saucepan. Cover with water and bring to the boil. Simmer for 40 minutes. Let it rest overnight refrigerated.
For the filling:
Mix the ricotta and sugar thoroughly in a large bowl. Add eggs and candied fruit and continue mixing. Add vanilla and orange flower water and keep mixing. Add the wheat kernels and stir until everything is well incorporated. Pour into pie shell. Cut 6 strips from the remaining pastry and criss-cross them over the top. Bake for 1 hour, 20 minutes
Pour the flour onto work surface in the form of a volcano. Make a hole in the top. Add sugar, eggs and butter and start to mix by kneading it from the outside in. Roll it out with a rolling pin until it's no more than 1/4-inch thick. Place in greased baking tin. Trim excess dough and cut into 6 even strips that will fit across the top of the pie.