Prep the sweet potato: Bake, microwave, or steam the sweet potato until very tender. Peel and mash until smooth. Measure out 1 cup and let it cool slightly so it doesn’t curdle the eggs.

Heat the oven and pan: Preheat the oven to 400°F (200°C). If using a cast-iron skillet, place it in the oven while it preheats. A hot skillet gives you crispy, caramelized edges.

Mix the dry ingredients: In a large bowl, whisk together cornmeal, flour, sugar, baking powder, baking soda, salt, and cinnamon. Break up any lumps so the crumb is even.

Combine the wet ingredients: In a separate bowl, whisk the eggs, buttermilk, melted butter, vanilla (if using), and mashed sweet potato. Stir until smooth and well blended.

Bring it together: Pour the wet mixture into the dry ingredients. Stir with a spatula just until there are no dry spots. Avoid overmixing—some small lumps are fine and keep the texture tender.

Prepare the pan: If using a cast-iron skillet, remove it carefully from the oven and swirl in a small knob of butter to coat. Otherwise, butter a 9-inch square pan or line it with parchment.

Bake: Scrape the batter into the prepared pan and smooth the top. Bake for 20–25 minutes, until the top is golden and a toothpick inserted in the center comes out with a few moist crumbs.

Rest and serve: Let the cornbread cool for 10–15 minutes before slicing. Serve warm with butter, honey, or a drizzle of maple syrup.