Prepare the pastry: Combine the flour, polenta, sugar and salt. Add the butter and mix on low speed for a few minutes or until the butter takes the shape of coffee beans. Keeping the mixer on the same speed, add the water, one tablespoon at a time. Mix until the dough begins to form a ball, 1 to 3 minutes.
Transfer the dough to a floured work surface. Roll out the dough with a rolling pin into a rectangular shape. Fold it in three like a letter. Roll the dough up in greaseproof paper or cling film and place it in the fridge for 20 minutes.
Prepare the fruit: Weigh the peaches and blueberries to have a total of 800g of fruit. Peel the peaches, removing the stones and cut them into 1.5cm slices. Add the blueberries, white wine or lemon juice and sugar. Place the fruit mixture in a colander above a bowl to collect the juice from the fruit. Cover the fruit and let it sit for 15 minutes.
Take the fruit juice that was collected and boil it for a few minutes, making sure the excess liquid has evaporated. You will end up with a kind of syrup that you will add to the fruit.
Preheat the oven to 190 C / Gas 5, placing the rack second from the bottom. Butter a 20-23cm pie dish and line with baking parchment.
Take the pastry from the fridge and roll it out and fold it again in three. Cut away 3/4 of the dough and put 1/4 in the fridge. Roll out the large piece to about 3mm and detach it from the work surface passing a thin blade or palette knife between the dough and work surface. Roll the pastry around the rolling pin and then transfer it to the pie dish. Pinch the edges every 3cm with your fingers. Place the dish in the fridge.
Roll out the remaining small piece of pastry, cut out whatever shapes you would like and enough to cover most of the top of the pie. Separate the shapes from the work surface using a knife, place them on a floured plate and in the fridge until you are ready to decorate the pie.
Take the pie dish with from the fridge, sprinkle the amaretti and savoiardi biscuits on the bottom and then place the fruit with the juice on top. Cover the top of the pie with the pastry shapes. Brush water on the edges and the shapes and then sprinkle with sugar.
Bake in the preheated oven for about 55 to 60 minutes or until the pastry is golden and the filling is bubbly. If the filling overflows while baking, place a tin underneath to catch the drippings. Let the pie cool in the tin for 3 hours and serve at room temperature.
You can prepare the pastry and the shapes the day before, cover and leave them in the fridge or freezer until you are ready to make the pie and bake it. If you don't have time to make the syrup, take 1 tablespoon of wine, mix 2 tablespoons of cornflour with the sugar and mix it all with the fruit.
The ratio of fat to flour for short crust pastry is off - as written it is Puff Pastry. I used a shallow tart pan as the amount of fruit is not enough to fill a deeper pie pan. With modifications stated this is a nice dessert. - 17 Sep 2012