Use a baking parchment paper to line two large baking sheets.
Use the plain flour to dust your working surface. Roll out the puff pastry into a rectangle shape—about 30.5 cm x 18 cm or 12” x 7”. If possible, roll out the pastry in one direction, without turning it—this will assist you in achieving an even rise. When done, trim the edges.
Spread your cream cheese/boursin evenly over the pastry. Lay the smoked nova salmon evenly over the cheese. Now, cutting down into the pastry—but not straight through, slice a line of ½” or 1 com in from the edges of the two short sides. This will assist you in rolling.
Next, roll the pastry inwards (tightly) from one short side—until you reach the center. Repeat this step on the other short side until it meets the first roll. Press them together to join them, and try to maintain the shape. Now, move the pastry, with the seam side facing down onto a board, and allow it to chill for around 30 minutes.
As the pastry chills, preheat your oven to 220 degrees C.
Use a serrated knife to cut ½” or 1 cm thick slices, from the roll—be careful not to squash the slices.
Lay these slices on the baking sheets, and leave a space of 1 ¼” or around 3 cm in between the rolls. Cover the pastries with another sheet of baking parchments. Now, roll the pastries gently using a rolling pin so that you can slightly flatten them. When done, remove the top sheet of the parchment paper.
Sprinkle the poppy seeds over the pastries, and bake for around 20 – 25 minutes, until they turn golden brown.
When done, move your smoked salmon swirls to a wire rack to cool. Serve.