In a large mixing bowl, combine 1 can drained whole kernel corn, 1 can cream-style corn, 1 cup sour cream, ½ cup melted butter, and 1 box (8.5 ounces) Jiffy Corn Muffin Mix.
Stir until all the ingredients are well combined.
Pour the batter evenly into the prepared baking dish.
Cook uncovered for 45-50 minutes or until lightly browned.
Remove the casserole from the oven and let it cool for 5–10 minutes before serving. Serve warm and enjoy.