Preheat your oven to 350°F. Lightly coat a 9×13-inch glass or ceramic baking dish with non-stick cooking spray and set it aside.

In a large saucepan set over medium heat, combine the drained whole kernel corn, cream-style corn, and the sliced pats of unsalted butter. Stir gently for 2 to 3 minutes until the butter melts entirely into the corn liquid.

Add the cubed, softened cream cheese, garlic powder, onion powder, sugar, salt, and black pepper directly into the saucepan.

Reduce the heat to medium-low. Use a sturdy spoon to stir the mixture continuously for 4 to 5 minutes, breaking up the cream cheese blocks until they melt completely and emulsify into a smooth, thick, and velvety white sauce baseline.

Stir in exactly ½ cup of the shredded sharp cheddar cheese, folding it into the warm corn matrix until it melts through. Remove the saucepan from the stove burner.

Pour the creamy corn mixture straight into the prepared baking dish, using a silicone spatula to spread it into a flat, even layer.

Scatter the remaining ½ cup of shredded cheddar cheese uniformly across the entire top surface of the casserole.

Place the dish uncovered on the middle oven rack and bake at 350°F for 25 to 30 minutes. The casserole is finished when the edges are bubbling aggressively and the top cheese layer is entirely melted and lightly golden.

Remove the dish from the oven and let it rest flat on a wire cooling rack for 5 to 10 minutes. This cooling window is vital, as it allows the hot cream cheese emulsion to naturally settle and tighten into a cohesive texture before serving.

Garnish the surface with a handful of fresh chopped chives for a bright pop of color and texturized contrast, then scoop and serve warm.