Place 1 inch of water in a large pot and fit it with a steamer basket. Add in the sweet potatoes, cover and bring to a boil. Reduce to a low boil and cook until the sweet potatoes are easily pierced with a fork, about 10-15 minutes
2 medium red garnet sweet potatoes
Transfer the sweet potatoes to a food processor and process until smooth. Measure out 1 cup. Save the rest for another use.
Preheat oven to 375°F. Spray an 11x7-inch baking pan with oil.
In a large bowl, whisk the cornmeal, flour, baking powder, baking soda, salt, cinnamon, and nutmeg together.
2 cups fine yellow cornmeal, 1 cup all-purpose flour, 1 tablespoon baking powder, 1 teaspoon baking soda, 1 teaspoon kosher salt, ½ teaspoon ground cinnamon, ½ teaspoon ground nutmeg
In a medium bowl, mix the pureed sweet potato, sugar, brown sugar, milk, sour cream, eggs, and butter together.
¼ cup granulated sugar, ¼ cup light brown sugar, 1 cup milk, ½ cup sour cream, 4 large eggs, ½ cup unsalted butter
Pour the wet ingredients into the dry and stir to combine.
Pour into the prepared baking pan and bake for 35-45 minutes. Let cool for 10 minutes before serving warm.