01 - Preheat your oven to 350°F (175°C). Grease a 9x9-inch baking dish or similar casserole dish.
02 - In a large bowl, combine the drained whole kernel corn, creamed corn, sour cream, melted butter, and Jiffy corn muffin mix. Mix until just blended.
03 - If using, stir in the shredded cheddar cheese.
04 - Pour the mixture into the prepared baking dish and spread evenly.
05 - Bake for 45–50 minutes, or until the top is golden and the center is set.
06 - Let rest for 5 minutes before serving.