Rhubarb-Raspberry Jalousie

Preparation Melt butter in heavy medium saucepan over medium heat. Add rhubarb. Cover and simmer until rhubarb is tender and falling apart, about 10 minutes. Add preserves and 1/4 cup sugar. Cook uncovered until very thick and reduced to 2 cups, stirring frequently, about 35 minutes. Refrigerate filling uncovered until cold, at least 1 hour. (Can be prepared 2 days ahead. Cover and keep refrigerated.) Preheat oven to 400°F. Line large baking sheet with parchment paper. Roll out pastry on lightly floured surface to 16x12-inch rectangle. Cut pastry in half lengthwise, forming two 16x6-inch rectangles. Place 1 rectangle on prepared baking sheet. Leaving 1-inch plain border, spoon filling onto pastry. Brush border with glaze. Top with second rectangle; press edges firmly to seal. Brush edges with glaze. Fold edges over, forming 1/2-inch border. Press border with tines of fork to seal. Brush top of pastry with glaze; sprinkle with 2 tablespoons sugar. Using sharp knife, cut 1 1/2-inch crosswise slits down center of pastry at 2-inch intervals, exposing filling. Bake pastry until golden brown, about 25 minutes. Cool pastry on sheet to lukewarm, about 45 minutes. Cut crosswise into 6 pieces. Serve with ice cream.

Preparation Melt butter in heavy medium saucepan over medium heat. Add rhubarb. Cover and simmer until rhubarb is tender and falling apart, about 10 minutes. Add preserves and 1/4 cup sugar. Cook uncovered until very thick and reduced to 2 cups, stirring frequently, about 35 minutes. Refrigerate filling uncovered until cold, at least 1 hour. (Can be prepared 2 days ahead. Cover and keep refrigerated.) Preheat oven to 400°F. Line large baking sheet with parchment paper. Roll out pastry on lightly floured surface to 16x12-inch rectangle. Cut pastry in half lengthwise, forming two 16x6-inch rectangles. Place 1 rectangle on prepared baking sheet. Leaving 1-inch plain border, spoon filling onto pastry. Brush border with glaze. Top with second rectangle; press edges firmly to seal. Brush edges with glaze. Fold edges over, forming 1/2-inch border. Press border with tines of fork to seal. Brush top of pastry with glaze; sprinkle with 2 tablespoons sugar. Using sharp knife, cut 1 1/2-inch crosswise slits down center of pastry at 2-inch intervals, exposing filling. Bake pastry until golden brown, about 25 minutes. Cool pastry on sheet to lukewarm, about 45 minutes. Cut crosswise into 6 pieces. Serve with ice cream.