Preheat oven to 350°F (175°C) and grease a 9×13-inch baking dish.

In a large bowl, combine the yellow cake mix, eggs, vegetable oil, sour cream, mashed sweet potatoes, vanilla extract, cinnamon, nutmeg, and ginger. Mix until smooth and well combined.

In a separate bowl, mix the brown sugar and cinnamon for the swirl.

Pour half of the cake batter into the prepared baking dish. Sprinkle the cinnamon-sugar mixture evenly over the batter.

Pour the remaining cake batter on top, spreading it to cover the cinnamon layer.

Bake for 40-45 minutes, or until a toothpick inserted into the center comes out clean.

Allow the cake to cool slightly in the pan while you prepare the glaze.

In a small bowl, whisk together powdered sugar, brown sugar, milk, and vanilla extract until smooth and pourable.

Pour the brown sugar glaze over the warm cake, allowing it to soak in slightly.

Let the cake cool to room temperature, then slice and enjoy!