Place the butternut squash into a large pot 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 350 degrees F (175 degrees C).
Mash the margarine into the butternut squash in a large bowl. Whisk together the flour, eggs, sugar, and non-dairy creamer in a separate bowl. Stir flour mixture into the butternut squash. Spread mixture into a 9x13 inch baking pan. Sprinkle with cinnamon.
Bake in the preheated oven until golden brown, about 1 hour.