Step 1: Preheat your oven to 350°F (175°C). Lightly grease a 9x13 inch baking dish. This will prevent your delicious corn casserole from sticking and make for easier cleanup. A little cooking spray or a pat of butter works wonders.
Step 2: In a large mixing bowl, combine the drained whole kernel corn and the undrained creamed corn. Stir gently to mix them evenly.
Step 3: Add the sour cream, melted butter, and corn muffin mix to the corn mixture. Do not add any additional ingredients that might be suggested on the corn muffin mix package (like eggs or milk), as they are not needed for this particular recipe.
Step 4: Stir all the ingredients together until just combined. Be careful not to overmix! Overmixing can lead to a tough or dry casserole. A few lumps from the corn muffin mix are perfectly fine and will dissipate during baking, resulting in a wonderfully tender casserole.
Step 5: Pour the mixture evenly into your prepared 9x13 inch baking dish. Spread it out with a spatula to ensure an even layer, which will help with uniform baking.
Step 6: Bake for 45-60 minutes, or until the top is golden brown and a toothpick inserted into the center comes out clean. The cooking time can vary slightly depending on your oven, so keep an eye on it. The edges should be set, and the center should no longer be jiggly.
Step 7: Once baked, remove the corn casserole from the oven and let it cool for about 10-15 minutes before serving. This cooling period allows the casserole to set properly, making it easier to scoop and serve. It also helps the flavors meld together beautifully. Serve warm and enjoy!