
Sift the flour into a large bowl then add the rest of the dry ingredients including the lemon zest, stir to combine.
Add the egg and butter and cut it into the flour mixture with a spatula or pastry scraper to form rough crumbs.
Start to bring the mixture together with your hands to form a dough. Knead the pastry until all the flour is fully absorbed and it becomes a smooth ball. Wrap in plastic wrap and place in the fridge for 30 minutes to 1 hour.
Pre-heat the oven to 350F/180C.
After the dough has chilled remove from the fridge and roll out using a rolling pin until ¼ inch (½ cm) thick.
Lay the pastry over a tart or pie pan tucking in the sides until it fits evenly. Trim the edges of the tart making sure to leave around 1/2 an inch (1 cm) overlap so you can fold it over later .
Prick the base with a fork then add the jam into the tart and spread it over the base evenly.
Roll the scrap pastry back into a ball and roll back out until 1/4 inch thick. Cut out strips for the top of the tart using a knife or pastry cutter.
Lay the strips of pastry over the crostata in a criss-cross pattern (or however you like) and fold the pastry edges around the tart over.
Bake in the oven for 45 minutes until golden brown, leave to cool completely then serve.