Preheat the Oven and Prepare the Pan: Preheat the oven to 375°F (190°C). Position a rack in the center.

Grease a 9 × 9-inch metal baking pan lightly with butter or nonstick spray.

For easier removal, line the bottom and two opposite sides with parchment paper, leaving a little overhang.

Prepare the Sweet Potato: Mash the cooked sweet potato until completely smooth. Measure 1 cup (240 g) and let it cool to room temperature if it is still warm.

The puree should be thick and spoonable: If it looks watery, let it drain briefly in a fine-mesh sieve before measuring.

Combine the Dry Ingredients: In a large mixing bowl, whisk together the cornmeal, all-purpose flour, baking powder, baking soda, kosher salt, and cinnamon.

Whisk thoroughly so the leavening agents and cinnamon are evenly distributed.

Mix the Wet Ingredients: In a medium bowl, whisk together the mashed sweet potato, eggs, buttermilk, honey, melted butter, and vanilla extract.

Continue whisking until the mixture is smooth and evenly blended.

A few very small sweet potato lumps are fine, but avoid leaving large pieces.

Make the Batter: Pour the wet mixture into the dry ingredients. Fold gently with a rubber spatula until no dry flour or cornmeal remains.

The batter should be thick but pourable: Stop mixing as soon as everything is combined to avoid developing excess gluten.

Fill the Pan: Transfer the batter to the prepared 9-inch square pan.

Spread it evenly into the corners and smooth the surface.

The batter should form an even layer so the center and edges bake at approximately the same rate.

Bake the Cornbread: Bake at 375°F (190°C) for 27–32 minutes. The top should be golden, the edges should begin pulling slightly away from the pan, and the center should spring back lightly when touched.

Insert a toothpick into the center: It should come out clean or with a few moist crumbs, but no wet batter.

If the top browns too quickly, loosely cover the pan with aluminum foil during the final few minutes.

Make the Honey Butter: While the cornbread bakes, stir together the melted butter, honey, and fine salt in a small bowl.

The mixture should look smooth and glossy: If the honey thickens the butter as it sits, warm it briefly until fluid again.

Brush the Warm Cornbread: Remove the cornbread from the oven and place the pan on a wire rack.

While the bread is still hot, brush the honey butter evenly over the surface.

Apply it gradually so the topping has time to soak into the warm crust rather than pooling in one area.

Cool Before Slicing: Let the cornbread cool in the pan for 20 minutes.

This gives the crumb time to set and allows the honey butter to absorb.

Cut into 9 squares and serve warm or at room temperature.