Boil the potatoes in their skins until they are 'al dente'.

Cool the potatoes, then peel and slice them.

Chop the onion and meat (or bacon).

Fry the chopped onion and meat/bacon in some oil; reserve the fried oil.

Chop the cornichons.

In a large bowl, mix the sliced potatoes, chopped cornichons, fried onions, and meat/bacon together with some of the fried oil (about 1 tablespoon).

Add mustard, salt, pepper, and crème fraîche to the mixture.

Stir well to combine all ingredients.

Add some of the cornichon juice to keep the salad moist.

Refrigerate the salad overnight to allow the flavors to meld.

If desired (for a variation without crème fraîche), omit the crème fraîche and add a bit more oil instead.

Serve cold.