Place the butternut pumpkin into a large saucepan and cover with salted water. Bring to a boil over high heat then reduce heat to medium-low, cover and simmer until tender; about 5 minutes. Drain and allow to steam dry for a minute or two.
Preheat an oven to 180 degrees C.
Mash the margarine into the butternut pumpkin in a large bowl.
Whisk together the flour, eggs, sugar and non-dairy creamer in a separate bowl.
Stir flour mixture into the butternut pumpkin. Spread mixture into a 20x30cm baking dish. Sprinkle with cinnamon.
Bake in the preheated oven until golden brown; about 1 hour.