01 - Preheat oven to 350°F. Grease a 9x13-inch baking dish or 2-quart casserole dish with butter or cooking spray.
02 - In a large mixing bowl, whisk together melted butter, sour cream, and eggs until completely smooth and well combined.
03 - Add drained kernel corn, creamed corn, and Jiffy Corn Muffin Mix to the bowl. Stir until all ingredients are fully incorporated and no dry mix remains. Season with salt and pepper if desired.
04 - Pour batter into the prepared baking dish and spread evenly with a spatula to ensure uniform thickness.
05 - Bake for 45 to 50 minutes, or until the top is golden brown and the center is set. A toothpick inserted in the center should come out clean.
06 - Let the casserole cool for 5 to 10 minutes before serving to allow it to set properly.