Preheat your oven to 350°F (175°C). Grease a baking pan.
In a mixing bowl, combine mashed sweet potatoes, sugar, brown sugar, and melted butter. Mix well.
Add eggs and vanilla extract to the mixture. Beat until smooth.
In another bowl, whisk together flour, baking powder, baking soda, salt, and cinnamon.
Gradually add the dry ingredients to the wet mixture, stirring until just combined.
Pour the batter into the prepared baking pan and spread evenly.
Bake for 45 minutes or until a toothpick inserted into the center comes out clean.
Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.