When the potatoes are done a sharp knife should be able to pierce a piece of potato easily and the potato should glide off the knife without falling apart.
Using a colander drain the water from potatoes and gently shake the potatoes in the colander to allow the excess water to drain away. Transfer the potatoes to a large bowl.
Meanwhile bring the chicken broth to a simmer over high heat in a small saucepan. Add the shallot cornichons and capers; reduce the heat to medium-low and simmer very gently.
Using a slotted spoon strain the cornichons shallots and capers from the broth and gently fold them into the potatoes. Using a silicone spatula gently toss the potatoes with the broth adding the broth gradually until most of the broth has been absorbed. Refrigerate the potatoes until they are cold tossing occasionally. As the mixture cools the potatoes will continue to absorb more broth.
Cook the bacon in a heavy large frying pan over medium heat until crisp and golden brown about 10 minutes. Transfer the bacon to a plate lined with paper towels and cool completely.
Chop the bacon as fine as possible in the bowl of a food processor. Transfer the bacon to a plate lined with paper towels.
Fold the mayonnaise into the cooled potatoes.
Add most of the bacon and 3 tablespoons of the parsley.
Gently fold the bacon and parsley into the potatoes. Season to taste with salt and pepper.
Garnish with the remaining bacon and parsley and serve.