Preheat your oven to 375°F (190°C). Grease a 9x9-inch (23x23 cm) baking pan with butter or non-stick cooking spray.

In a large mixing bowl, whisk together the cornmeal, all-purpose flour, sugar, baking powder, and salt until well combined.

In another bowl, combine the mashed bananas, buttermilk, melted butter, eggs, and vanilla extract. Mix until the wet ingredients are well incorporated.

Pour the wet ingredients into the bowl with the dry ingredients. Stir gently until just combined. Be careful not to overmix; a few lumps are okay. Overmixing can result in dense cornbread.

Pour the batter into the prepared baking pan, spreading it out evenly. Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.

Once the cornbread is baked through, remove it from the oven and let it cool in the pan for about 10 minutes. Then, transfer the cornbread to a wire rack to cool completely before slicing.

Slice the banana cornbread into squares and serve warm or at room temperature. Enjoy it on its own, with butter, or as a side dish to your favorite savory meals.