Preheat oven to 400 degrees F.

Coat a 12-tin muffin pan with nonstick cooking spray.

In a medium bowl whisk together flour, cornmeal, baking powder, baking soda, and salt. Set aside.

In another bowl, whisk together eggs until they turn a light color and are well-combined.

Add sugar to eggs and whisk quickly until thick and well-blended.

Add melted butter to egg mixture in a couple of additions, whisking after each addition to combine well.

Add half of the sour cream and half of the milk to the wet ingredient mixture. Mix to combine. Add remainder milk and sour cream and combine.

Add wet ingredients to dry and stir in gently with a rubber spatula until the batter is moistened and just coming together. Mixture should be evenly moistened, but should look a little lumpy. DO NOT OVERMIX!

Drop spoonfuls of batter into prepared muffin tin (using a big ice cream scoop works well). Do not level or flatten surfaces.

Bake for 16-18 minutes, or until muffins are light golden brown and toothpick inserted into muffin comes out clean.

Let muffins stand for 5 minutes in tin, then remove, and serve warm.