Begin by melting the butter, then let it cool to room temperature.
Preheat your oven to 180°C (350°F).
Grease a 23 cm (9") springform cake pan or line it with parchment paper.
In a mixing bowl, whisk together the melted unsalted butter, milk, and eggs.
In a separate bowl, combine the cornmeal, plain white flour, baking powder, baking soda, sugar, and salt. Mix these dry ingredients thoroughly.
Gradually add the dry ingredient mixture to the wet ingredients, stirring until you have a smooth batter.
Now, fold in the finely chopped jalapeno, finely sliced green onions, and grated cheddar cheese into the batter. Ensure they are evenly distributed.
Pour the batter into the prepared springform cake pan, spreading it out evenly.
Bake in the preheated oven for approximately 30-35 minutes or until the cornbread is golden brown on top and a toothpick inserted into the center comes out clean.
Remove the Mexican-inspired cornbread from the oven and allow it to cool in the cake pan for a few minutes.
Once it has cooled slightly, you can release it from the springform pan, cut it into wedges or squares, and serve.