- 1 1/2 pounds white potatoes, scrubbed
- 3 1/2 tablespoons extra-virgin olive oil
- Freshly ground pepper
- 1 tablespoons grainy mustard
- 2 1/4 teaspoons sherry vinegar
- 1/2 small sweet onion, thinly sliced (1 cup)
- 2 1/2 ounces baby arugula (4 cups)
Preheat the oven to 425°. Cut the potatoes into 1/2-inch wedges. Scatter the potato wedges on 1 large rimmed baking sheet, drizzle with 1 1/2 tablespoons of the olive oil and toss until coated. Season with salt and pepper and roast for about 25 minutes, until browned and crisp.
In a small bowl, whisk the remaining 2 tablespoons of olive oil with the mustard and vinegar and season with salt and pepper. In a large bowl, toss the potatoes with the onion and arugula. Top with the dressing, toss again and serve right away.