Preheat the oven to 200C. Cut the pastry into two equal pieces and place each onto a lightly flour dusted sheet of baking paper. Roll out both pieces of pastry to 20x30cm rectangles.
Starting with one piece, carefully cut out your tree shape. The easiest way to achieve a symmetrical shape is to fold the pastry in half lengthways, then from the bottom edge nearest you, measure 2cm out from the fold and cut the tree trunk by cutting vertically upwards 4cm. From the top of the ‘trunk’, cut horizontally across to the edge of the pastry, to create the lowest tree ‘branch’. Now, place a ruler (or similar straight edged utensil) placing it at the very top point of the folded pastry furthest away from you, to where it meets the bottom of the ‘branch’. Unfold the pastry and you should now have a triangular shaped tree. Use this tree as a template by lifting both baking paper and pastry on top of the other rolled out piece.
Gently press a knife around the outline of the tree trying not to cut through the baking paper, but enough to leave an indent of the shape onto the pastry beneath. Place the tree to one side whilst you cut the second tree shape.
Using a small star cutter, cut out 2 stars. Spread 150g mincemeat evenly over one of the trees and stars, then grate the marzipan over the mincemeat. Carefully place the other tree and star directly on top of the mincemeat covered ones, and press gently but firmly to sandwich them together.
Now using the ruler, gently press a central column trunk of 2cm from the bottom of the trunk to the top of the tree. Cut the branches of the tree by working on one side of the central column, cutting horizontals of 1.5 cm from the column out to the edges of the triangle. Keep going until you reach the top of the tree. Now following the same measurements, do the exact same horizontal cuts on the opposite side. Take the lowest horizontal ‘branch’ on one side of the tree, and gently twist away from you twice, placing it back down on the baking paper neatly. Take the next branch and repeat, working up with each piece until the branches are too small to twist, usually the top one. Take care not to twist too much in case the pastry tears, so as the branches become shorter, only twist once.
Repeat with the opposite branches. Place your star at the top of the tree and press lightly to join them. Brush the tree lightly with beaten egg or milk, and sprinkle with the sugar. Bake for 15-20 minutes until golden brown and crisp.