- 1 sheet frozen puff pastry (half of 17 1/4-ounce package), thawed
- 1/4 cup seedless raspberry jam
- 1 large egg
- 1 tablespoon whipping cream
- Preheat oven to 375°F. Roll out pastry on floured surface to 12×9-inch rectangle. Cut pastry in half lengthwise, creating two 12×4 1/2-inch strips. Place 1 pastry strip on large baking sheet. Spread jam evenly over pastry, leaving 1/2-inch border on all sides. Fold remaining pastry strip in half lengthwise. Using small knife and beginning 1/2 inch from 1 end of pastry, cut slit through fold to within 1/2 inch of unfolded side of pastry. Repeat cutting slits at 1/2-inch intervals. Unfold dough and open flat on work surface. Whisk egg and cream in small bowl to blend. Brush cut pastry with some of egg mixture. Brush edges of jam-covered pastry strip with some of egg mixture. Place cut pastry strip over strip with jam, egg-glazed side up. Press edges firmly to seal.
- Bake tart until pastry is golden, about 25 minutes. Transfer sheet to rack and cool 5 minutes. Using large metal spatula, loosen tart from sheet. Slide tart onto rack and cool completely. (Can be prepared 6 hours ahead. Cover and let stand at room temperature.)