Dilled Potatoes Vinaigrette
- Cut the potatoes lengthwise into fourths and in a steamer set over boiling water steam them, covered, for 7 to 10 minutes, or until they are just tender.
- In a bowl whisk together the mustard, the vinegar, the vermouth, and salt to taste, add the oil in a stream, whisking, and whisk the dressing until it is emulsified.
- Add the potatoes while they are still warm to the dressing and toss them gently with the dressing, the dill, and pepper to taste until they are coated well.
- Let the potato mixture stand, tossing it occasionally, for 30 minutes and serve it at room temperature.
- The potato mixture may be made 1 day in advance and kept covered and chilled. Let the potato mixture return to room temperature before serving.