Preheat your oven to 350°F (175°C).
Prepare a loaf pan by greasing it lightly.
In a large mixing bowl, combine the mashed sweet potatoes, granulated sugar, brown sugar, and vegetable oil.
Add in the eggs and vanilla extract, and whisk until smooth.
In a separate bowl, whisk together the flour, baking powder, baking soda, cinnamon, and salt.
Gradually fold the dry mixture into the wet mixture until just combined.
If desired, fold in chopped walnuts or pecans.
Pour the batter into the prepared loaf pan and smooth the top.
Bake in the preheated oven for 50-60 minutes.
Allow the bread to cool in the pan for 10 minutes.
Transfer the bread to a wire rack to cool completely.
Slice and enjoy your delicious sweet potato cinnamon bread!