Preheat Oven: Preheat oven to 350°F (175°C). Grease a 9x13-inch baking dish.
Combine Wet Ingredients: In a large bowl, mix drained corn, creamed corn, melted butter, sour cream, eggs, and shredded cheddar cheese until smooth.
Add Dry Ingredients: Stir in cornmeal, flour, baking powder, salt, and pepper until just combined. Do not overmix.
Transfer to Baking Dish: Pour mixture into prepared baking dish and smooth the top. Sprinkle additional cheddar cheese on top if desired.
Bake: Bake for 40–45 minutes, until the top is golden and the casserole is set in the center.
Cool and Serve: Let cool for 5–10 minutes before serving. Garnish with chopped green onions if desired.