Prepare the Sweet Potato
Bake or microwave a sweet potato until soft. Mash it until smooth, then let it cool to room temperature.
Make the Cake Batter
Preheat your oven to 350°F and grease a 9x13-inch baking dish.
In a large mixing bowl, whisk together the flour, granulated sugar, brown sugar, baking powder, baking soda, cinnamon, nutmeg, and salt.
In a separate bowl, mix the mashed sweet potato, eggs, oil, milk, and vanilla extract until well combined.
Gradually add the wet ingredients to the dry ingredients, mixing until just combined. Do not overmix. Pour the batter into the prepared baking dish.
Add the Cinnamon Swirl
In a small bowl, mix the melted butter, brown sugar, and cinnamon until smooth.
Drop spoonfuls of the cinnamon mixture over the cake batter and use a knife to swirl it throughout the cake.
Bake the Cake
Bake for 35-40 minutes, or until a toothpick inserted into the center comes out clean. Allow the cake to cool slightly before glazing.
Make the Glaze
Beat the cream cheese until smooth. Add the powdered sugar, milk, and vanilla extract, mixing until creamy. Adjust the consistency with more milk if needed.
Glaze the Cake
Drizzle the cream cheese glaze over the warm cake. Use an offset spatula to spread it evenly if desired.
Serve
Slice and serve warm or at room temperature