Heat oven to 350°F; grease 2-quart dish with teaspoon butter. Whisk cornmeal, flour, sugar, baking powder, and salt.

Separately mix creamed corn, drained kernels, sour cream, eggs, and melted butter evenly.

Fold dry ingredients into corn mixture just until no dry flour remains. Pour into dish; smooth top.

Bake 40 to 45 minutes until edges golden, center set, and middle thermometer reads 160°F.

Stand 10 minutes; serve in soft squares or spoonfuls.