Quick Pear Napoleans

Preheat oven to 400°F with rack in upper third.

Roll out pastry with a floured rolling pin on a lightly floured surface into about a 16-inch square. Trim edges.

Transfer to a parchment-lined baking sheet and place another baking sheet on top.

Bake until golden and cooked through, 15 to 18 minutes.

Remove top baking sheet from pastry and transfer pastry to a rack to cool completely.

While pastry cools, beat heavy cream with an electric mixer until it just holds

soft peaks. Fold in sour cream gently but thoroughly.

Meanwhile, cook sugar in a dry large heavy skillet over medium heat until it begins to melt, then continue to cook, stirring with a fork, until it is completely melted and golden. Stir in reserved pear syrup and boil, stirring, until thickened,

3 to 5 minutes. Stir in pears.

Remove from heat and swirl in butter until combined.

Cut pastry into 8 rectangles with a large knife.

Place half of rectangles on 4 serving plates.

Spread cream mixture over pastry, then spoon pears with caramel over top.

Place remaining pastry rectangles on top.