Directions

1. In a small saucepan, heat milk until small bubbles form. Drop in the vanilla pod, remove saucepan from heat, and set aside to cool until just warm. In a medium saucepan, stir together the flour, sugar, salt, and egg yolks. Beat for a moment, then gradually whisk in warm milk. Simmer over medium-low heat until the custard thickens, stirring constantly with a wooden spoon to prevent sticking. Transfer custard to a bowl, and allow to cool, stirring from time to time.
2. Preheat oven to 400 degrees F (200 degrees C). Roll out the puff pastry into a single sheet about 1/2 inch thick; it should be the same size as a 17x14 inch baking sheet. Place the pastry onto the baking sheet, and prick all over with a fork.
3. Bake in preheated oven for 28 minutes. Remove from oven, and cool pastry on the baking sheet.
4. When the pastry has cooled completely, transfer it from the baking sheet to a hard surface, and cut lengthwise into three 4 to 5 inches wide strips. Spread one strip thickly with custard. Place a second strip directly over the first; spread the top evenly with jam. Cover with the third strip, and dust with confectioners' sugar. With a very sharp knife, cut into 8 rectangular portions.