For the Pasta Frolla, combine dry ingredients in food processor and pulse to mix. Cut butter into 8 pieces and add. Pulse to mix in finely. Add eggs and pulse until dough forms a ball. Remove from work bowl, wrap and chill dough.
Soak the wheat in water to cover overnight if possible. Drain the wheat and place in a pan with salt and water to cover by 3 to 4 inches and simmer until tender, about 2 hours. Add water as necessary to keep from drying out and sticking. Cool and refrigerate until needed.
For the pastry cream, combine sugar and flour in a small, non-reactive saucepan. Stir well to mix and add the milk, slowly, whisking it in smoothly. Whisk in the egg. Cook over low heat, stirring constantly, until the pastry cream thickens and comes to a boil. Boil, stirring vigorously, about 1/2 minute. Remove from heat, stir in vanilla and scrape into a clean bowl. Press plastic wrap against the surface and chill.
For the filling, place ricotta in a mixing bowl and stir the cooled pastry cream to make a smooth, creamy mixture; stir in the sugar, eggs and remaining ingredients. Stir in the cooked wheat kernels.
Preheat oven to 350 degrees and set a rack in the lowest level. Butter a 9-inch cake pan, 2-inches deep. To assemble, cut off 1/3 of the Pasta Frolla and reserve it. Roll the 2/3 of the dough into a 14-inch disk and line the prepared pan with it. Allow the dough to hang over the edge of the pan. Pour in the filling and sprinkle it with the cinnamon. Roll the remaining 1/3 of the dough into a 10-inch square. Cut it into 10 1-inch wide strips. Paint the strips with the egg wash. Moisten the rim of the dough on the pan with the egg wash, and adhere 5 strips in each direction, forming a diagonal lattice. Trim away any excess dough even with the top of the pan and push the dough all around off the top rim of the pan so that it is completely within the pan.
Bake about 45 minutes, until the filling is set and the pastry is light golden. Cool in the pan before unmolding. To unmold, invert onto a flat plate, lift off the pan, replace the pan with another plate or platter, then re-invert, so that the Pastiera is right side up. Serve the Pastiera at room temperature.