Sift together the flour, baking powder and salt. Set aside.
In a food processor. pulse together the lemon zest and sugar.
Add the whole egg, the egg yolk and vanilla extract. Give it a whirl for 20 seconds.
Next, add the safflower oil and process for 15-20 seconds.
Add the dry ingredients (flour, baking powder, and salt) and pulse together until the mixture resembles coarse breadcrumbs. The dough should stick together when gently squeezed.
Transfer the dough to a wooden board which has been lightly floured.
Gather the dough together and form a log. Just in case you are wondering, this dough requires no kneading.
Divide into two balls -one about 2/3 of the dough which will form the bottom layer of the crostata and the other 1/3 will become the top. Wrap in plastic wrap and refrigerate for at least 30 minutes.
Place oven grate to bottom third of the oven. Preheat oven 400° F.
Roll out the larger piece of dough to fit your tart pan. In order to facilitate the transfer of the dough to your tart pan, roll out the dough between two pieces of parchment paper.
Slide the parchment paper (and the dough) on a cookie sheet and place in the refrigerator while you roll out the smaller piece of dough that will form the lattice top. Once again, transfer to a cookie sheet and place in the refrigerator. Pull out the first piece of dough.
Quickly flip the dough and the parchment paper over the tart pan and slowly peel back the parchment paper. Press dough into the edges of the pan. If the dough breaks (like mine) simply use the scrapes of dough to patch up.
With the times of a fork, simply prick a few holes in the base of the crust.
Spread a thin layer of jam over the bottom part of the dough.
Pull out the smaller piece of rolled dough from the refrigerator. Cut into strips with a pastry wheel, about ½ inch, and arrange over the jam. Start by placing the longest strip straight across the middle, followed by one or two strips on either side. This will form your bottom layer of lattice strips. Then criss-cross with 4 more strips. If you still have dough, you can cover the sides with it. Gently press the sides together, securing the ends to the bottom crust.
Brush a little of the egg wash over your lattice work (NOT the jam).
Bake in a 400° F oven for about 30 minutes or until the crust is golden brown.
Allow to cool completely before removing form the tart pan and serving.