In a small saucepan over medium heat, melt butter. Add flour and whisk for 1 minute. Slowly pour in the milk and heavy cream, whisking constantly until blended.
Add frozen corn, 1 teaspoon sugar and a couple pinches of salt. Stir to mix. Bring to a boil and reduce heat to low. Cook for 15 - 20 minutes or until the sauce is reduced and thickened, stirring often. Season with more salt and pepper. Taste and adjust with more sugar if needed. Transfer to a serving bowl.
Notes
For the consistency of the sauce, it should be creamy and just thick enough to coat the corns. You don't want it too runny.
You can easily double or triple the recipe for more servings.