Cook bacon in a large skillet until crisp; remove bacon, and drain on paper towels, reserving 1 tablespoon drippings in skillet. Crumble bacon, and set aside.
Melt butter in hot drippings over medium heat; add onion, and saute until tender.
Whisk in flour and salt until smooth and bubbly. Whisk in sour cream until smooth; cook, whisking often, 3 minutes. Stir in corn, and cook until thoroughly heated. Spoon into a lightly greased 8-inch baking dish; top with crumbled bacon.
Bake at 350° for 15 to 20 minutes or until bubbly.