Pre-heat oven to 350F (180C). Grease and flour an 8 or 9 inch (20-22 cm) pie plate.
First make the Pumpkin Pastry Cream, if you want the flavors to mingle even more, then let the cream cool to room temperature, cover it with plastic wrap, make sure the plastic is touching the cream and refrigerate for a couple of hours or even overnight. Bring the cream to room temperature, stir to combine and continue with the recipe, or you can let the cream cool a bit before using.
While the pastry cream is cooling, make the dough, this dough can be made in a food processor or by hand, place the flour, sugar and baking powder in a larger bowl or the bowl of your food processor, whisk to combine.
Make a well in the middle (if in the bowl) and add the egg, yolk and butter, cut into small pieces, mix together with a fork, or pulse until almost combined.
Move the dough to a lightly floured flat surface and gently and quickly bring together to form a compact ball. If you are making it by hand you will need to knead it a bit longer to bring it together.
Wrap the dough in plastic and refrigerate for at least 30 minutes or even overnight.
Remove the dough from fridge, knead the dough a couple of times to soften it up again. On a floured flat surface. Roll out to 1/8″ thickness.
Transfer the dough to the prepared pie plate. Trim the dish of any extra dough. Prick the dough with the tongs of a fork, then spread the pastry cream evenly on top.
With the extra dough make strips to create a lattice finish (see photos). Brush the top of the pastry lightly with milk and bake for approximately 25-30 minutes, if the crust is browning too much then cover with foil and continue baking. Let the crostata cool then slice, top with fresh whipped cream if desired. Enjoy!
The pastry can also be made using a stand up mixer with the flat beaters, beat on low speed and do not over mix. It's best to bring it together by hand.If you have any leftovers, it should be covered in plastic and refrigerated. It will keep for up to 2-3 days in the fridge. You can bring it to room temperature before serving.To freeze the crostata, make sure it has cooled completely, then wrap it in plastic wrap, then again in foil. Place it in a freezer safe bag or container and freeze. It will last up to 3 months in the freezer. Thaw in the refrigerator. It’s not really a good idea to freeze the unbaked pie, as the pastry cream could separate.You can make both the cream and the dough a day before, just remove them from the fridge and leave them on the counter for about 30 minutes, then put it together as instructed in the recipe.