Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the sweet corn, cream-style corn, sour cream, melted butter, and shredded cheddar cheese. Mix well until all ingredients are evenly combined.
Add the Jiffy corn muffin mix, salt, and black pepper to the bowl. Stir until just combined; do not overmix.
Pour the mixture into a greased 9x13-inch baking dish, spreading it evenly.
Bake in the preheated oven for 45-50 minutes, or until the top is golden brown and a toothpick inserted in the center comes out clean.
Allow to cool for about 10 minutes before serving.