Remove kernels: Cut off tip of each cob; stand in a wide shallow bowl. With a sharp knife, slice downward to remove kernels.
Stand each cob over another wide shallow bowl. With the edge of a soup spoon, scrape downward to remove pulp.
In a medium saucepan, melt butter over medium heat. Add onion, and cook, stirring frequently, until softened, 2 to 3 minutes. Add corn kernels, pulp, and 3/4 cup water. Bring to a boil. Reduce to a simmer; cover, and cook, until corn is tender, 10 to 15 minutes.
Add cream and sugar; simmer, uncovered, until cream has thickened, 4 to 6 minutes. Season with salt and pepper. Serve.