Preheat the Oven: Set your oven to 400°F (200°C). Grease your baking dish or line it with parchment paper for easy cleanup.
Mix Dry Ingredients: In a large bowl, combine the cornmeal, polenta, flour, baking powder, and salt. Stir until the mixture is evenly distributed.
Combine Wet Ingredients: In a separate bowl, whisk together the eggs, melted butter, milk (or buttermilk), and sugar (if using). Mix until fully incorporated.
Combine Wet and Dry: Slowly pour the wet ingredients into the dry mixture, stirring just until combined. Be careful not to overmix, as this could make the cornbread dense.
Bake: Pour the batter into your prepared baking dish. Spread it evenly with a spatula and bake for 20-25 minutes, or until the top is golden and a toothpick inserted into the center comes out clean.
Cool and Serve: Allow the cornbread to cool slightly before serving. Enjoy warm with butter, honey, or your favorite topping.