4 large sweet potatoes (2 ½ to 3 pounds total), peeled and cut into 1-inch cubes ¼ cup plus 2 to 3 tablespoons extra-virgin olive oil 1 cup thinly sliced celery (about 3 stalks) ½ small red onion, thinly sliced ½ cup thawed and shelled frozen edamame 2 tablespoons fresh lemon juice 1 tablespoon Dijon mustard Salt and freshly ground black pepper ¼ cup chopped fresh parsley 1 tablespoon minced fresh chives Toasted pepitas (pumpkin seeds; see Tip) for optional garnish
- Preheat the oven to 400°F.
- Put the cubed potatoes on a large baking sheet (or two, if you can’t get them all on in a single layer). Drizzle the potatoes with 2 to 3 tablespoons of the olive oil, ensuring all the cubes are coated. Spread the potatoes out in a single layer. Roast for 25 to 30 minutes, until the potatoes are tender and browned, stirring them halfway through. Set aside.
- In a large bowl, stir together the celery, red onion, and edamame. Stir the potatoes into the onion mixture and set aside.
- In a small bowl, whisk together the remaining ¼ cup olive oil, lemon juice, and mustard. Drizzle the vinaigrette over the potatoes and toss gently. Season with salt and pepper. Stir in the parsley and chives and serve immediately, or cover and refrigerate, adding the parsley and chives just before serving so that the herbs remain crisp and fresh, not wilted. Sprinkle with pepitas, if you like added crunch.
Tip: To toast pumpkin seeds, preheat the oven to 375°F. Toss the seeds lightly with olive oil, then spread them out on a rimmed baking sheet. Cook until crispy and light brown, 6 to 8 minutes, stirring them halfway through.