Preheat the oven to 400 degrees F (200 degrees C).
Cut the Fingerling Potato (2 pound) in half lengthwise and place them on a sheet pan. Add Extra-Virgin Olive Oil (2 tablespoon), Kosher Salt (1 teaspoon), Freshly Ground Black Pepper (1/4 teaspoon), and the Whole Grain Mustard (2 tablespoon) to the potatoes, and toss well with your hands to coat.
Roast for 30 to 40 minutes, tossing occasionally until the potatoes are tender and browned all over. Once cooked, transfer to a medium bowl.
In a small bowl, whisk together the Fresh Dill (2 tablespoon), Fresh Parsley (2 tablespoon), White Wine Vinegar (1 tablespoon), Extra-Virgin Olive Oil (1 tablespoon), and Kosher Salt (1/2 teaspoon). Pour the dressing over the hot potatoes, toss, and serve hot, warm, or at room temperature.