Preheat oven to 350°F (175°C). Grease a 9x13-inch baking dish.
In a large mixing bowl, combine whole kernel corn, creamed corn, sour cream, and melted butter. Stir until blended.
Fold in the corn muffin mix just until combined, do not overmix.
Stir in ¾ cup of the shredded cheddar cheese.
Pour the mixture into the prepared baking dish and spread evenly.
Bake for 45–50 minutes until the top is golden and the center is set.
Five minutes before the end of baking, sprinkle the remaining ¼ cup cheese on top and continue baking.
Let the casserole rest for 5–10 minutes before serving. Garnish with parsley or green onions if desired.