Preheat your oven to 375°F (190°C).

Roll out the thawed puff pastry on a lightly floured surface until it's about 1/8 inch thick.

Wash, peel (if desired), and slice the ripe pears thinly. Toss them with cinnamon, sugar, and lemon juice.

Neatly arrange the pear slices on the puff pastry, leaving about a 1-inch border around the edges.

Brush the edges of the pastry with melted butter and sprinkle any remaining cinnamon-sugar mixture over the pears.

Place the baking sheet in the oven and bake for 25-30 minutes, until the pastry is golden brown.

Optional: Brush the top of the tart with warm apricot jam for a glossy finish.

Allow the tart to cool slightly on the baking sheet for about 5-10 minutes before serving.