Preheat your oven to 350°F and generously butter a 9x13-inch baking dish. Pat the corn kernels dry using paper towels to remove surface moisture that could create a soggy casserole texture.

Melt 4 tablespoons butter in a large skillet over medium heat, then sauté the diced onion and bell pepper for 5–7 minutes until softened and fragrant. Season lightly with salt and pepper while cooking, allowing the vegetables to release their natural juices into the buttery base.

In a separate bowl, whisk together heavy cream, chicken broth, and eggs until completely combined and smooth. Add salt, black pepper, garlic powder, and paprika to the mixture, whisking thoroughly to distribute seasonings evenly throughout.

Combine the corn kernels, sautéed vegetables, cornbread crumbles, and cheddar cheese in a large mixing bowl. Pour the cream mixture over this combination and gently fold everything together until the buttery fall corn casserole ingredients are evenly coated and distributed without overmixing.

Transfer the mixture into your prepared baking dish, spreading it level with a spatula. In a small bowl, mix panko breadcrumbs with 1 tablespoon melted butter, then sprinkle this topping evenly across the casserole surface.

Bake for 35 minutes until the top turns golden brown and a knife inserted into the center comes out clean. Do not overbake, as the casserole will continue cooking slightly after removal from heat—watch for the edges to bubble and the center to set firmly.

Remove from the oven and let it rest for 5 minutes before garnishing with fresh parsley. This resting period allows the custard to set completely while maintaining optimal serving temperature.