If you're starting with a real pumpkin, as opposed to canned, cut it into quarters, scrape out the seeds and bake it until soft.
Cool. Scoop out the pumpkin and mash well.
In a bowl, mix the pumpkin and egg. Stir in the flour, cinnamon, salt and pepper. Knead briefly on the counter to incorporate the flour and make a smooth sticky dough. Wrap in plastic and refrigerate for an hour.
Bring a pot of salted water to a rolling boil. Using a teaspoon, scoop up a ball of dough, roll it off the spoon with your fingers and drop into the boiling water.
If the dough is sticky, dip the teaspoon in cold water between each scoop.
When the gnocchi float to the surface, scoop them out with a slotted spoon into a serving bowl. There will be too much dough to cook all at once, so do the gnocchi in batches.
Meanwhile, in a saucepan, heat the butter with oil and garlic. Chop the sage into slivers and add to the butter. When the first batch of gnocchi is in the bowl, remove the garlic and pour the butter over the gnocchi, stirring lightly to coat.
Keep each batch warm in a low oven. Serve warm, sprinkled with pepper and Parmesan cheese.