Preheat oven to 350F Lightly spray a standard loaf pan and line with a sheet of parchment paper with long ends so you can lift it out later for coating with butter and cinnamon sugar.
In a large mixing bowl whisk the eggs together until well combined. Then whisk in the sugar.
Whisk in the vegetable oil and soft butter, then the pumpkin and vanilla. Blend until smooth.
Whisk in the baking powder and salt, and then fold in the flour. Turn the batter into the prepared loaf pan and spread out evenly. Bake for 45-50 minutes, or until a toothpick inserted in the center comes out without wet batter on it (moist crumbs are fine.) Cover loosely with foil toward the end of baking if the bread seems to be browning too quickly.
Let cool for 10 minutes, then remove from the pan.
Stir together the sugars and cinnamon. Brush the entire surface and sides of the warm bread with the melted butter. Then immediately coat liberally with the cinnamon sugar.