Preheat oven to 350°F. Butter an 11x7 or other 2-quart baking dish. Set aside.
In a large bowl, whisk the butter, sour cream, and eggs together until well combined.
½ cup unsalted butter, 1 cup sour cream, 2 large eggs
Stir in the corn kernels and creamed corn.
15 ounces canned corn kernels, 15 ounces canned creamed corn
Add in the Jiffy and mix until just combined.
8.5 ounces Jiffy corn muffin mix
Fold in ½ cup of the cheese.
1½ cups freshly shredded cheddar cheese
Pour into the prepared pan and spread into an even layer, topping with the remaining cheese.
Bake until the cheese is melted and the casserole is set in the center, about 40-50 minutes. Serve warm.