Open the oven quickly and remove the wire rack Reduce the oven temperature to 300°F/150°C and bake for another 35 to 40 minutes, until the puff pastry is a rich brown color all the way through Remove from the oven and turn on the broiler Flip the puff pastry over so that the top is now even and flat, and dust with confectioners’ sugar Place under the broiler, about 3 inches away from the heat, and watch carefully as the top caramelizes This should not take more than a minute or two Do not move away from the oven, as once the sugar begins to caramelize it will rapidly burn, and there goes your puff pastry As soon as you see the sugar caramelize remove the puff from the oven and allow it to cool completely Transfer the mousseline to a pastry bag fitted with a ½-inch round tip Place the baked puff pastry on a cutting board and trim the sides so that you have a perfect rectangle Measure the puff, and, using a long serrated knife, carefully cut lengthwise into 3 evenly sized rectangles They should be approximately 3 inches wide by 12 inches long You will be cutting the assembled mille-feuille into 6 portions that should each measure approximately 2 ì 3 inches Place a long strip of puff pastry on your work surface with the caramelized side facing up Pipe rows of round ẵinch balls of mousseline onto the rectangle Place the second rectangle of ... Place a long strip of puff pastry on your work surface with the caramelized side facing up Pipe rows of round ½inch balls of mousseline onto the rectangle Place the second rectangle of ... move away from the oven, as once the sugar begins to caramelize it will rapidly burn, and there goes your puff pastry As soon as you see the sugar caramelize remove the puff from the oven and allow it to cool... Transfer the mousseline to a pastry bag fitted with a ½-inch round tip Place the baked puff pastry on a cutting board and trim the sides so that you have a perfect rectangle Measure the puff, and, using a long