Preheat the oven to 375°F (190°C/Gas Mark 5).

Wash the pears and cut them in half lengthwise. Brush the cut sides with a little lemon juice, then sprinkle with the brown sugar and a little ground cinnamon, if you wish.

Line a baking sheet with parchment paper and place the pears, cut side down, on it. Spoon a little jam onto the rounded side of each pear.

Roll out the puff pastry to a thickness of about ¼ in. (5 mm) and lay it over the pear halves. Using a sharp knife, cut the pastry around each half, so it is completely covered with a pastry shell. You can use the dough trimmings to cut out fun shapes, such as small branches and leaves, to decorate the shells. Brush the shapes with a little water and press them gently onto the pastry shells to attach them.

Cut 2 small slits in each pastry shell to let steam escape. Sprinkle them with cinnamon and granulated sugar, if you wish. Bake for 20–25 minutes, until the pastry is golden brown.

Let cool for 1–2 minutes, then carefully turn each pear half over. Serve warm or at room temperature.