Cook bacon in a large, deep skillet over medium-high heat, turning occasionally, until evenly browned, about 10 minutes. Drain on a paper towel-lined plate.

Add butter, flour, and salt to the skillet; whisk with drippings over medium heat until butter melts. Add cabbage and cook, stirring occasionally, until tender, about 15 minutes. Crumble bacon into the skillet. Stir in sour cream and cook until heated through, 1 to 2 minutes.