Potato Salad with Grainy Mustard Vinaigrette

8 servings
Time to prepare: hands-on time: 15 minutes total time: 1 hour 30 minutes (includes marinating)

Ingredients
3 lbs potatoes (such as Yukon Gold), peeled and cut to 1 inch cubes
1 tbsp kosher salt
3/4 Basic Vinaigrette
2 tbsp coarse-grain mustard
1 small bunch fresh tarragon, roughly chopped (if desired)
1/4 tsp freshly ground black pepper

Directions
Place potatoes and salt in medium pot with enough cold water to cover by 2 inches. Bring to boil. Reduce heat and simmer until the potatoes are fork-tender, about 15 minutes. Drain and transfer to serving dish. Whisk together the vinaigrette and mustard in a small bowl. Pour half the mixture over the hot potatoes, toss, and let stand 1 hour. Just before serving, drizzle the remaining vinaigrette over the potatoes, add the tarragon (if desired) and pepper, and toss.