1. In a stand mixer bowl place butter, sugar, salt and zest. Beat with the paddle until light and fluffy.

2. Add eggs a bit at a time while beating eggs. Stop the machine, add the flour all at once and mix until with spatula until incorporated. Dough should be crunchy and crumbly but easy to cut.

3. Wrap dough in plastic film and refrigerate for at least 2 hours or overnight.

4. Work dough quickly on a floured surface, just enough to make it pliable, then roll and use about 2/3 of the dough to line a tart pan. Fill the dough-lined pan with jam. With the rest of the dough cut strips about 1 in wide and arrange them on top of the jam to create a lattice or checkered pattern. (At this stage the tart can be wrapped in plastic and frozen for up to 2 months.)

5. Brush the top of the crostata with a beaten egg and sprinkle some raw sugar on top if desired. Bake at 350 for about 40 min. (lower the temperature if the top is browning too fast).

6. Let cool completely before serving and do not refrigerate leftovers.

Tip: use powdered sugar instead of flour for rolling. Roll between parchment paper and use wooden rulers for even thickness of the rolled dough.