Preheat your oven to 350°F and lightly butter a 2-quart or 2 1/2-quart casserole dish with high sides.
In a bowl, mix the whole kernel corn, cream-style corn, salt, beaten egg, melted butter, sugar, sour cream, and corn muffin mix until just combined.
Pour the mixture into the prepared dish and bake for 45-55 minutes, or until the soufflé is set but still moist. Baking time may vary depending on the shape of the dish. If using, garnish with chopped parsley.