Preheat Oven: Heat oven to 375°F (190°C). Grease an 8-inch pan or line with parchment.
Mix Dry Ingredients: In a large bowl, whisk cornmeal, flour, sugar, baking powder, baking soda, and salt.
Combine Wet Ingredients: In another bowl, whisk together buttermilk, melted butter, and eggs until smooth.
Blend Wet and Dry: Pour wet ingredients into dry mix. Stir gently until just combined—avoid overmixing.
Optional Add-ins: Fold in corn kernels, cheese, or jalapeños if desired.
Bake: Pour batter into pan and bake 20–25 minutes, until a toothpick inserted in the center comes out clean.
Cool and Serve: Let cool slightly, then cut into squares and serve warm with butter or toppings of choice.