Fry bacon until crisp, drain and crumble. Boil potatoes until tender, drain, cool and cut into 1/4 inch slices.
Whisk together vinegar, sour cream, oil, and salt and pepper. Add onion, 1/2 of the parsley and 1/2 of the bacon. Pour over potatoes and toss gently. Chill for at least 6 hours. Garnish with the remaining bacon and parsley.
