Prepare two 9 by 5-inch loaf pans by spraying generously with cooking spray and lining the bottom of each pan with parchment paper. Spray the parchment paper and sprinkle each pan with a light dusting of flour, tapping out any excess flour over the sink. Set aside.
Divide the refrigerated dough in half and keep one half covered in plastic wrap in the fridge. Roll out one half of the dough on a lightly flour surface into a rectangle approximately measuring 15 by 10 inches.
Use an offset spatula to alternately spread half the chocolate mixture and half the pumpkin mixture in alternating stripes across the rolled out dough — it should look like a bumblebee made from chocolate and pumpkin:
Use both hands to roll the long side of the rectangle like a roulade, starting from the long side that is closest to you and ending at the other long end:
Trim about 3/4-inch off both ends of the roulade with a serrated bread knife or sharp bench scraper. Now use the knife to gently cut the roll into half lengthwise, starting at the top and finishing at the seam — you're essentially dividing the log into two long even halves, with the layers of dough and filling visible along the length of both halves:
Shift the halves so that the cut sides with the exposed filling are facing up. Bring the sides together, and start braiding the sides by lifting the right half over the left half, then the left half over the right half, repeating until the two are fully intertwined:
Gently squeeze together the ends.
Carefully lift the braid into a prepared loaf pan:
Cover the pan with a wet flour cloth (but not terrycloth!) and leave to rise in a warm place for 1 to 1 1/2 hours. The cake will rise by 10 to 20 percent.
Repeat the whole process to make the second cake.