Remove kernels: Stand a cob of corn on a kitchen-towel-lined baking sheet. With a sharp knife, slice downward to remove kernels. Repeat with remaining ears. With the edge of a soup spoon, scrape downward to remove pulp.
In a large skillet, melt butter over medium heat. Add onion and cook, stirring frequently, until softened, 2 to 3 minutes. Add corn kernels, pulp, and 1 cup water. Bring to a boil. Reduce to a simmer; cover, and cook, stirring occasionally until corn is very tender, 20 to 25 minutes.
Add cream and sugar; simmer, uncovered, until cream has thickened, 4 to 6 minutes. Season with salt and pepper. Serve.