In a large skillet, melt the butter over medium heat. Add the frozen corn and season it with salt, pepper, and fresh thyme. Stir everything together and cook for about 5–7 minutes, or until the corn is heated through and some of the excess moisture has evaporated.
Sprinkle the flour and sugar over the corn and stir until everything is evenly coated. Continue cooking for about 1–2 minutes.
Slowly pour in the heavy cream and whole milk, stirring until everything is combined. Stir in the Parmesan cheese and adjust the salt and pepper if needed.
Let the corn gently simmer over medium-low heat for about 4-6 minutes, stirring frequently, until the sauce has thickened and coats the corn nicely.
Transfer the mixture to a lightly greased baking dish and spread it out evenly. Sprinkle the remaining Parmesan cheese over the top and bake uncovered for about 20 minutes, or until the cream corn is hot and bubbling around the edges. Let it rest for about 5–10 minutes before serving. Enjoy!