Firstly, mill the flour. I like to weigh my wheat berries, that way I know I am getting the right amount of flour in grams as well.
Warm the water to around 90*F. Just warm to the touch, not too hot.
Then, in a stand mixer, add the warm water, brown sugar, melted butter, salt, pumpkin puree, and pumpkin pie spice. Mix to combine.
Add the freshly milled flour to the wet ingredients, and mix to incorporate all the dry flour. Cover, and let sit at room temperature for at least 15 minutes. This will allow the fresh milled flour to soften and start to absorb the liquids.
After this first rest period, then add in the yeast, and start the kneading process. (see video if any questions about the texture of the dough.) The kneading process may only take 8 minutes, but could take up to 25 minutes. It should be a loose wet dough.
I like to knead the dough until it is nice and stretchy without breaking too easily. Make sure to check on the stretchiness of the dough every couple minutes, as to not over knead the dough.
Once the dough is nice and stretchy, heavily butter a 9x13 baking dish with softened butter. Make sure to butter up the sides of the pan as well.
Place the dough into the butter pan, and gently spread the dough in the pan, trying not to tear the dough. It is ok if the dough doesn't fill the pan to the edges, it should double in size after the first rise.
Cover the dough, and let it rise to double. This should take between 1 and 2 hours.
During the first rise, make the topping/swirl mixture.