Preheat the oven to 425˚F (220˚C). Line a large baking sheet with parchment paper.
On a heavily floured work surface, scoop out the dough with a spatula. With lightly floured hands, shape the dough into a rough rectangle. Use a floured rolling pin to roll out the dough into an 1/8-inch thickness (~16x12-inch rectangle).
Use a spatula to spread the roux over the dough leaving ½-inch space all around the edges.
Begin at one long end and roll up the dough like a cinnamon roll to the other end. Pinch the seam at the end to seal it and rotate the roll so that the seam faces up.
Use a knife and divide the dough into 8 relatively equal roll pieces.
Move all but one roll of dough out of the way from the center of the workspace. Seal the cut edges as you move them. Place one roll in the center of the work surface. Pinch to seal the cut sides again, if needed.
To make the flaky, layered center, rotate one roll (if not already) so the center seam is facing up while the cut and sealed edges are at a right angle facing your left and right. Roll the dough away from you and towards you to 5 inches in length.
Make a trifold (envelope shape) with the top and bottom. Fold the top down a third of the way. Fold the bottom up a third of the way.
Repeat the same process with the same roll of dough. Rotate the dough so now the cut and sealed edges are facing away and towards you (one side is farthest away from you while the other is towards you). Roll the dough out again to 5 inches in length and repeat with the trifold (envelope shape).
Set the roll aside and continue the process with the remaining 7 rolls of dough. Cover and allow the rolls to rest for 10 minutes.
Meanwhile, place the sesame seeds in a small flat plate or dish.
With damp hands, lightly dampen the smooth side of a roll dough and place the smooth side down on top of the sesame seeds. Press down on the dough lighlty so the seeds stick to the dough. Remove the dough from the seeds. With the sesame side facing up, roll the dough into a 6x3-inch rectangle. Place the rectangle on the large parchment-lined baking sheet. Repeat with remaining 7 rolls of dough. Space each rectangle 1-2 inches apart on the baking sheet.
Place the baking sheet in the oven on the center rack and bake for 12-15 minutes or until the top is golden brown.