Heat olive oil in a cast iron skillet over medium heat. Add diced onion and sauté until translucent, about 5 minutes.

Stir in minced garlic and cook for an additional minute until fragrant.

Add black beans, kidney beans, diced tomatoes, chili powder, cumin, salt, and corn. Stir well and let simmer for 10 minutes.

In a mixing bowl, combine cornmeal, flour, baking powder, and salt.

In another bowl, whisk together milk, egg, honey, and melted butter.

Pour the wet ingredients into the dry ingredients and mix until just combined.

Preheat the oven to 400°F (200°C).

Pour the cornbread batter over the chili filling in the skillet, spreading it evenly.

Bake in the preheated oven for 20-25 minutes, or until the cornbread is golden brown and a toothpick comes out clean.

Let it cool for a few minutes before serving.