Take the puff pastry out of the fridge. Wash the lemon hot, dab dry and finely grate the peel. Squeeze the lemon. Wash the pears, quarter them lengthwise and cut the flesh into thin slices. Mix pears with lemon juice and peel.
Preheat oven (electric cooker: 200 °C/circulating air: 180 °C/gas: see manufacturer). Roll out puff pastry. Cut off 5 strips approx. 1 cm wide from one short side. Brush the rest of the dough with water at the edges. Place strips of dough on top as a border.
Boil the jelly briefly. Spread pear wedges fan-shaped on the dough. Spread the pears and puff pastry edges generously with the warmed jelly and bake for about 40 minutes. Remove the finished tart from the oven, dust with cinnamon and allow to cool.