Preheat your oven to 200°C (390°F) and lightly grease a 12-cup muffin tin or line it with paper liners, ready for the batter.
In a large mixing bowl, whisk together the cornmeal, all-purpose flour, sugar, baking powder, and salt until evenly combined. This creates a rustic, textured dry mixture.
In a separate bowl, beat the eggs until frothy, then stir in the sour cream, melted butter, and milk, mixing until smooth and slightly thickened.
Pour the wet mixture into the dry ingredients and gently fold together with a spatula, just until combined. Be careful not to overmix; a few lumps are fine and help keep the muffins tender.
Divide the batter evenly among the muffin cups, filling each about three-quarters full. The batter should be thick but scoopable, with a slightly uneven top surface.
Bake in the preheated oven for 18-20 minutes, until the muffins are golden on top and a toothpick inserted into the center comes out clean. The tops will crack slightly, signaling perfect doneness.
Remove the muffins from the oven and let them rest in the tin for about 5 minutes—this helps set the crumb and makes them easier to remove.
Transfer the muffins to a wire rack to cool slightly or serve warm straight from the oven. Enjoy their warm, fragrant aroma and tender crumb that stays moist even after a day.