The nonna's tart (in Italian "torta della nonna") is a typical sweet of the Italian cuisine, made out of pasta frolla filled with the classic Italian pastry cream (crema pasticcera), and covered with pine nuts and powdered sugar. Pasta frolla is a typical and delicate Italian sweet shortcrust pastry, that usually forms the base for most crostatas, and it's made out of butter, eggs, sugar, and flour. In Italy exist also a variant of this typical sweet, called "torta del nonno" (nonno's tart): in Italian, nonna means grandmother, and nonno means grandfather.
Prepare the cream
Put the milk and the non-treated lemon zest in a little pot and wait until it boils. When it starts to boil, turn off the heat. In a pot, whip with a whisk 4 egg yolks with 3 oz of granulated sugar; when the mix turns clear and fluffy, add 2 oz of flour, and whip until the mix turns creamy and without lumps. Dilute the mix with the strained milk, pouring it little by little and stirring with a whisk. Put the pot on low heat and cook, continuing to stir until the cream gets dense. Turn off the heat, add one ounce of butter, and pour the pastry cream in a bowl, then cover it with a plastic film: let it cool at room temperature.
Prepare the pasta frolla
Pour on the pastry board 14 ounces of flour, and create a nest. Add in the center of the nest 7 ounces of butter, cut in little pieces, the yeast for sweets, 6 ounces of sugar, and a pinch of salt. Quickly knead the ingredients until you obtain a crumbly mixture. Create a nest with the mixture, add the egg and the lemon zest in the center of it. Knead again with your hands, shape a ball, wrap it in the plastic film, and put it in the fridge for one hour.
Complete your tart and cook
Line with baking paper a cake mold with a diameter of 10 inches; the baking paper has to be previously soaked and drained. Roll on the floured pastry board 2/3 of the pasta frolla, the layer must be 1/4 of an inch thick; place the pasta frolla in the mold, and with a knife remove the excess of pasta along the edges. Create very little holes in the pasta frolla layer, and pour on it the pastry cream. Quickly knead on the floured pastry board the remained pasta frolla and create a disk with a thickness of 1/4 of an inch; cover the top of the tart with this last layer of pasta frolla. Seal the edges by pushing down the extremity of the pasta frolla. Put the pine nuts in cold water for 10 minutes, then distribute them on the surface of the nonna's tart, gently pressing them on the pasta frolla. Bake at 390°F for 40-45 minutes. Sprinkle the nonna's tart with powdered sugar, and serve it cold.