Peel all the pears, halve and remove core. Fill the cavities with marzipan.
Divide pastry into 3 equal pieces; roll out one third to a rectangle approx. 20x40cm/8x16" cut into 8 equal squares, repeat with remaining pastry pieces.
With a sharp knife slice through the pears but leave pointed end intact. Place one pear half diagonally on a pastry square, pressing pear lightly to slightly 'fan' it. Brush the pastry edges with beaten egg white then bring up the corner nearest the rounded end of the pear and press onto pear. Brush again and sprinkle with caster sugar.
Bake for 12 - 15 minutes until pastry is risen and golden. Gently heat jam, sieve to remove the large pieces of fruit. Brush each pear with melted jam and allow to cool before serving.