Preheat your oven to 400 degrees F. Place a piece of parchment on your work surface. (I find it easiest to assemble this on a piece of parchment and then move it to the baking sheet.) Unroll the first piece of puff pastry and lay it on the piece of parchment.
To a small bowl, mix together the pumpkin puree, brown sugar, pumpkin pie spice and salt. Spread the pumpkin puree, in an even layer, all over the (12-inch) round or puff pastry, like you would a pizza with marinara sauce, stopping about 1/2-inch from the edges. Place the second round of puff pastry on top, pressing it down slightly, pushing out any air bubbles.
At this point, since I was taking a bit of time, I found my puff pastry to be too soft to cut, so I transferred it to the freezer for 5 minutes. When I took it out, it was perfect. (If yours is flimsy, I suggest doing this, too.) Set a small drinking glass in the center of the puff pastry circle and start by cutting the pastry in 4, starting at the edge of the glass and going outward. Then slice each quarter into 2. And then cut each eighth into 3. You should end up with about 24 twists, but really you'll be ok as long as you don't make the twists too big.
Twist each strip gently, starting at the center and then working your way outward, giving the twist support the entire time, to avoid breakage. I gave each strip about 5 to 6 turns. Repeat with the remaining strips. If the ends are jagged, feel free to take a sharp paring knife and trim the ends. Remove the glass and brush the entire thing with egg yolk and transfer to the freezer to chill for 10 minutes. Then bake for 15 to 20 minutes, until evenly golden brown.
Meanwhile, in a stand-up mixer (you can also use a hand-mixer), combine the heavy cream, creme fraiche and maple syrup. Beat until soft peaks form, about 1 to 2 minutes. Serve alongside the spiral twists.