Before you shape the dough, you'll need to mix the filling. Mix the filling ingredients together in a small bowl. Set aside until you're ready to shape the dough.
Once the sourdough pumpkin babka dough as risen around 50%, tip the dough out onto a clean surface and push out into a rectangle that measures around 16" x 8" (it really doesn't have to be exact).
Spread the filling you prepared earlier over the whole rectangle, leaving a 1" border on one of the long sides.
Roll the dough up into a log, finished on the side with the border of dough you left unfilled. Tuck the seam underneath the log.
Take a dough scraper or bench knife and slice the log in half length ways, leaving a small section still attached at one end.
Now twist the two lengths of dough into a rope, twisting it so that the filling is swirled around the dough.
Roll each end up so that the dough forms an "S" shape and carefully lift it into your chosen loaf pan.
Place an elastic food cover over the pan and allow the dough to rise up (around 50%) so that it fills the tin.
While the sourdough pumpkin babka is proofing, make a simple sugar syrup by placing the sugar and water in a small saucepan and heating until the syrup is just boiling, Turn down the heat and let it simmer for around 5 minutes, moving the syrup around the pan occasionally. Once the syrup starts to thicken, remove from the heat and place into a bowl to cool.