Let the pizza dough proof for one hour at room temperature.
While the dough proofs, heat the oil up in a medium pan over medium heat. Add in the onions and stir to coat in oil. Cook, stirring occasionally, until then onions are brown, soft and caramelized. You may need to turn down then heat half way through. This takes 30-40 minutes.
Once the onions are almost done, stir in 1/2 tsp of the cinnamon and all of the ginger, nutmeg and allspice. Cook until done.
Add in the pumpkin, milk, sugar, salt and remaining cinnamon and stir.
Place the butter in a small sauce pan over medium heat. Cook, stirring frequently until it melts and starts to foam. When it starts to foam, stir it constantly until it turns golden brown.
Once it's brown, immediately remove it from the heat and stir well into the sauce.
Heat a large pan on medium high heat and sear the sliced sausage and both sides until browned, about 1-2 minutes per side.
Heat just enough oil to cover the bottom of a small pan on high heat. Once hot, add in the sage leaves and cook until lightly browned, only about 1 minute. Transfer to a paper towel lined plate.