1

In a large pot, cover the potatoes with cold salted water and bring to a boil over moderately high heat. Cook until the potatoes are tender, about 35 minutes. Drain the potatoes and, when they are cool enough to handle, slice them in half.

2

Meanwhile, in a medium skillet, cook the bacon slices over moderate heat until crisp, about 6 minutes. Drain on paper towels and coarsely crumble.

3

In a large bowl, mix the mayonnaise with the barbecue sauce, mustard and sherry vinegar. Fold the potatoes into the dressing while they are still warm. Let the potato salad stand, stirring a few times, until the potatoes have cooled and absorbed most of the dressing, about 20 minutes.

4

Add celery, red onion, parsley and tarragon to the potatoes and season with salt and pepper. Let stand for an additional 20 minutes, stirring a few times. Garnish with the bacon, then serve.