Preheat oven to 425°F. Scrub the sweet potato and place it on a tray in the center of the oven. Roast for 40–50 minutes or until the sweet potato is soft and its skin is wrinkled. Remove from the oven and let the potato sit on a rack until it’s cool enough to handle, but still warm enough that it’s easy to peel. Put the skin in your compost bucket and purée the sweet potato flesh in a food processor. Measure out 1 cup of purée and reserve the rest for another use.
In a medium mixing bowl, whisk together the flour, cornmeal, brown sugar, baking powder, salt, and cinnamon until combined. Set aside.
Heat a 10-inch cast iron skillet in the oven until it’s hot. Drop 2 tablespoons butter into the skillet to melt. Swirl to make sure the pan is well coated on the bottom and sides.
Place the cup of sweet potato purée in a large bowl and add the milk and eggs. Mix well and then whisk in 1/4 cup melted butter. Fold in the dry ingredients, mixing until dry mixture is fully moistened.
Pour batter into the hot buttered skillet and bake for 40-45 minutes. Your nose knows when it’s done—you should smell it before you open the oven.
Optional: You can spread some butter on top of the hot cornbread when it comes out of the oven.
Serve with Wanda’s Southern-Style Braised Mustard Greens.