Bring a large pot of salted water to a boil. Add the potatoes and cook until tender, adjusting the heat so that the potatoes stay at a simmer, about 8 minutes. Drain and spread out on a rimmed baking sheet.
Meanwhile, in a large bowl, whisk together the olive oil, vinegar, scallions, shallots, mustard, parsley, basil, thyme, dill and salt and pepper.
Pour the vinaigrette over the warm potatoes on a baking sheet and gently toss and spread them out again. Allow the potatoes to cool to room temperature, and soak up the dressing. Adjust seasonings to taste. Transfer to a serving bowl and serve at room temperature.