Cut the sheet of pastry in half lengthways and place onto a lined baking tray. Brush with egg wash. Top with another piece of baking paper and place a second baking tray on top. Bake for 20 minutes at 180℃, remove the top baking tray and bake for 5 minutes or until baked through and golden. Set aside to cool completely.
Stir the caramel treat until smooth, then spread onto one of the pastry pieces. Top with the second piece of pastry and press down slightly.
Allow the melted chocolate to cool slightly so that it is not too runny, then pour over the top of the pastry.
Chill in the fridge until set.
Cut into bars using a sharp serrated knife dipped in boiling water. Store in the fridge.