In a large bowl put in flour and soft butter. Chop the butter into pea size pieces.
Add in pumpkin puree, maple syrup, sourdough starter, and milk. Mix into a shaggy dough. Then knead until it becomes a nice ball.
Cover with a light towel or cling wrap and let sit overnight.
For the filling: make the night before, after the dough. Mix together melted butter, cinnamon, and sugar. Let sit on counter overnight to solidify.
In the morning, mix together in a small bowl the salt, baking soda, and baking powder.
Dump the dough out on a floured surface and knead in the baking soda, baking powder, and salt mixture.
Roll out the dough into a 1/4 - 1/2 inch thick rectangle.
Spread sugar filling evenly over the dough. Roll up.
Cut into 1/2 -1 inch slices and place into a pan, I use cast iron.
Bake at 350º F for 25 minutes.
While they cook, boil the butter and maple syrup together until a candy thermometer reads 240º F.
Drizzle over warm sticky buns.