Preheat oven to 350 degrees F.
Grease a 9 x 13 casserole dish.
In the casserole dish (or a large bowl), add the melted butter, Jiffy mix, whole kernel corn (with liquid), creamed corn, egg, and half the shredded cheddar cheese (about 1 cup). Mix everything until well combined.
Once the large lumps have been mixed out, pour the batter into a greased 9 x 13 casserole dish.
Dollop the sour cream evenly over the top, then gently swirl it in with a knife for a marbled effect (don’t fully mix it in).
Bake for 45 minutes, or until golden brown. Then sprinkle the rest of the cheddar cheese on top, and return to the oven for 5 more minutes.
Serve warm, and enjoy this cheesy, creamy, rich cornbread that’s packed with corn!