Preheat the oven to 350°F (175°C) and prepare your baking pan by greasing and flouring it.

In a large mixing bowl, combine mashed sweet potatoes, softened unsalted butter, and granulated sugar. Beat with a hand mixer for about 2-3 minutes until smooth and creamy.

Add eggs one at a time, mixing well after each addition, then add sour cream and mix until well combined.

In a separate bowl, whisk together all-purpose flour, baking powder, baking soda, ground cinnamon, ground nutmeg, and salt.

Fold the dry ingredients into the wet mixture gently using a rubber spatula until just combined.

Pour the batter into the prepared baking pan, smoothing the top evenly.

Bake for 45–60 minutes, checking for doneness with a toothpick.

Let the cake cool in the pan for 10 minutes, then transfer it to a wire rack to cool completely.

To prepare the glaze, combine powdered sugar with milk or cream and stir until smooth.

Once cooled, drizzle the glaze over the cake and serve.