Preheat the oven to 350ºF. In a large bowl, whisk together the pumpkin purée, eggs, oil, molasses, and sugar.
In a separate bowl, stir together the flour, cinnamon, ginger, nutmeg, salt, and baking powder.
Pour the dry ingredients into the bowl of wet ingredients, and stir them together just until combined. It's okay if there are a few small lumps. Avoid over stirring.
Coat the inside of a loaf pan with butter. Pour the batter into the loaf pan and spread it out smooth.
Bake the pumpkin bread for about one hour, or until the internal temperature reaches 200ºF, or a toothpick inserted into the center comes out clean (a few crumbs are okay, just no raw batter stuck to the toothpick).
Transfer the bread to a wire rack to cool, then slice and serve.