Heat the olive oil in a Dutch oven or deep skillet over medium heat. Cook meat on all sides until browned. Add the beef broth and water; bring to a boil. Reduce heat to medium low; cover and simmer until tender, about 30 minutes.
Remove the meat rolls. Strain the broth mixture and return liquid to the Dutch oven or skillet. Whisk together the cornstarch and 1 C. of water. Slowly pour the cornstarch slurry into the skillet, stirring continually until the sauce has thickened, 2 to 3 minutes. Stir in the sour cream. Return rolls to the sauce; serve immediately.