Heat the oven to 350°F and grease a 2-quart baking dish with the teaspoon butter. Whisk cornmeal, flour, sugar, baking powder and salt in a bowl.
In a second bowl, stir together creamed corn, drained kernels, sour cream, eggs and melted butter until evenly mixed.
Fold the dry ingredients into the corn mixture just until no dry flour remains. Pour into the dish and smooth the surface.
Bake for 40 to 45 minutes until the edges are golden, the center is set and a thermometer in the middle reads 160°F.
Let stand for 10 minutes before serving in soft squares or spoonfuls.