Heat oven to 325ºF. Coat a 9-by-5-by-3-inch loaf pan with butter and flour.
Sift the flour, cinnamon, baking soda, baking powder, and salt together.
In a separate bowl, mix the sugar, vegetable oil, eggs, and vanilla. Combine both mixtures and fold in the shredded pumpkin and pumpkin seeds. Once all the ingredients are incorporated, pour into the prepared loaf pan.
Bake for 1 hour and 15 minutes. At this point, a knife inserted into the middle of the loaf should come out clean. Cool for 15 minutes and turn out onto a cooling rack. Cool completely. For muffins, temperature should also be 325ºF, but bake for 30 minutes.