Add the all-purpose flour, yeast, brown and white sugar, and pumpkin pie spice mix to the bowl of a stand mixer. Mix it all together so that things are well-combined.
In a microwave safe bowl, heat the buttermilk, pumpkin puree,
butter, and oil for 1 minute. Whisk it all together until well-combined.
Fold the warm pumpkin mixture into the dry ingredients and
add the egg. On low speed, knead the dough for 5-7 minutes. If the dough looks too soft, and things haven't combined well enough, add up to ½ cup of additional flour. The dough will be pretty shaggy, and this is okay. Just make sure that there are no pockets of flour hiding under the ball of dough, especially at the bottom of the bowl. Mix those in with a spatula.
Scoop the dough out onto a piece of parchment paper. Spray the bowl of the stand mixer with cooking spray. Return the
ball of dough to the now lubricated bowl. Cover the bowl with plastic wrap, and cover the plastic wrap with a clean kitchen towel.
Put the bowl in a warm, draft-free place, and let it rise until doubled in size (about 2 hours).
When the dough is nearly done rising, line a 9x13-inch pan
with parchment paper, spray it with cooking spray, and set it aside. Alternatively, spray two 9-inch round cake pans, and set aside.