Preheat the oven to 400°F (200°C). Grease a 9-inch square baking pan.
In a large bowl, whisk together the cornmeal, flour, sugar, baking powder, and salt.
In a separate bowl, whisk together the milk, melted butter, and egg.
Pour the wet ingredients into the dry ingredients and stir until just combined.
Pour the batter into the prepared baking pan and smooth the top.
Bake for 20-25 minutes, or until the top is golden brown and a toothpick inserted into the center comes out clean.
Remove from the oven and let cool for a few minutes before slicing and serving.