Place 1 1/2 pounds of cubed potatoes in a large pot and cover them with cold water. Add a pinch of salt, turn the heat to high, and bring the water to a rolling boil. Once boiling, reduce the heat to a simmer and cook for 8-10 minutes or until the potatoes are just tender and can be pierced with a fork. Drain the potatoes and set them aside to cool.

In a medium mixing bowl, combine 2 tablespoons of olive oil, 2 tablespoons of red wine vinegar, 1 tablespoon of Dijon mustard, and 1 tablespoon of cornichon juice (if using). Add 1 grated garlic clove for extra flavor and season with salt and pepper to taste. Whisk the ingredients together until emulsified and creamy.

In a large mixing bowl, combine the cooled potatoes with 3 tablespoons of chopped parsley, 3 tablespoons of chopped dill, and 3 thinly sliced green onions. If using, add the finely diced shallot and 1/4 cup of diced cornichons. Gently toss the ingredients together using a spatula.

Pour the prepared dressing over the potato mixture. Using a large spoon, carefully toss everything together until the potatoes are evenly coated with the dressing.

Cover the salad and place it in the refrigerator for at least an hour. Serve chilled or at room temperature.