Preheat oven to 325°F/160°C.
When the dough is ready, roll out the dough on a lightly floured surface, into the shape of the baking sheet. Roll it out to about ½ cm thick, or ¼ inch thick and place on top of the parchment. Cut the edges of the dough off, and set aside for the lattice ribbons.
Spread a layer of homemade apricot jam across the pie. The surface area of the dough should be completely covered with the apricot jam.
With the remaining dough, roll out into thin strips the length of the pie. The strips should be about 3 cm wide, and rolled out flat, not round. For a fancier effect, slice small symmetrical cuts diagonally along the length of the dough strip (resembling a christmas tree effect). When this cooks, it will resemble a leafy vine.
Take the egg wash and lightly brush on all the exposed dough pieces.
Place in the the oven for about 20 minutes until the dough starts to turn golden brown. Check that the base of the pie is cooked underneath. If needed, keep in oven for another 5-10 minutes, keep checking until you are happy with it. Mine took around 25 minutes.
Remove from the oven, cool and serve with tea or a glass of milk.