Remove the husks and silks from the corn. For stability cut one end the cob so it is flat.
Place it in a large bowl. Using a sharp knife, slice the kernels off the cob.
Once all the kernels have been removed, use the back side of the knife and scrape the cob, releasing the pulpy, milk-like liquid.
Mince the onion and cut the green onion, separating the green and white parts, set them aside.
Add the flour, sugar, salt, and pepper to a small bowl. Stir it all together.
Stir in the seasoned flour mixture into the corn until it is all lightly coated.
Pour in the heavy whipping cream and milk. Stir well.
Heat the skillet over medium heat and add the butter, once melted sauté the onion and white parts of the green onions until softened, about 2 minutes.
Add the corn mixture to the skillet and simmer, stirring frequently, for 30 minutes, or until the corn is cooked through and the cream has reached the desired consistency.
Garnish with the reserved green portion of the green onions and serve.
Notes
Scrape the cobs. Use the back of the knife to release the starchy corn milk. It thickens the dish and adds pure corn flavor.
Keep the heat gentle. A low simmer in cast iron reduces the cream evenly without scorching the bottom or breaking the sauce.
Stir often so the flour does not catch on the pan.
Taste at the end for salt, pepper, and sugar. Corn sweetness varies ear to ear.
Adjust the texture. Too thin? Simmer a few minutes longer. Too thick? Loosen with a splash of warm milk.
Bacon version. Fry chopped bacon, add it at the end, and swap the butter for the bacon grease.
Gluten-free. Skip the flour and melt in 8 oz cream cheese after the onions, or stir in a cornstarch slurry during the last 10 minutes.