Preheat your oven to 350°F (175°C). Grease a 2-quart baking dish with butter or non-stick spray.
In a large mixing bowl, combine the corn kernels, whole milk, sour cream, and melted butter. Mix until blended.
Add the eggs one at a time, beating well after each addition to ensure a fluffy mixture.
In another bowl, whisk together the sugar, baking powder, salt, black pepper, and onion powder. Slowly add this dry mixture to the wet corn mixture, stirring until just combined.
If using, fold in the shredded cheddar cheese for extra flavor.
Pour the corn pudding mixture into the prepared baking dish, smoothing the top with a spatula.
Bake in the preheated oven for 45–55 minutes, or until the pudding is set and the top is golden brown. A knife inserted in the center should come out clean.
Let the corn pudding cool for about 10 minutes before serving.