Preheat your oven to 350°F (175°C). Grease a 9.25 x 5.25 inch loaf pan, then line it with parchment paper.

In a large mixing bowl, cream the softened butter and white sugar together until light and fluffy (about 2-3 minutes).

Add the eggs one at a time, mixing well after each addition. Mix in the vanilla extract and mashed sweet potatoes until combined and smooth.

In another bowl, whisk together the all-purpose flour, baking soda, salt, ground cinnamon, and nutmeg. Gradually add these dry ingredients to the wet mixture, stirring gently until just combined.

In a small bowl, combine the remaining sugar and cinnamon for the topping. Set aside.

Pour the batter into the prepared loaf pan, then evenly sprinkle the cinnamon-sugar topping on top. Bake for 55-65 minutes or until a toothpick inserted comes out clean.

Let the bread cool in the pan for 15 minutes, then carefully transfer it to a cooling rack to cool completely before slicing.