PURPLE POTATO SALAD WITH PEA VINES
INGREDIENTS
1/3 cup plus 3 tbsp. extra-virgin olive oil, divided
1 1/4 pounds sweet onions (about 2 medium onions), chopped
3 pounds mixed purple- and red-skinned potatoes, halved and then cut into 1/2-inch slices
3 tbsp. Kosher salt, divided
7 tbsp. cider vinegar, divided
10 cups water
2 tsp. grainy mustard
1/2 tsp. black pepper
5 ounces pea vines, roughly chopped
1/3 cup pitted and chopped Kalamata olives
1/3 cup thinly sliced scallion (about 3 medium-size scallions)
1 red Fresno chile, seeded and diced
PREPARATION
1. In a large skillet over medium-high heat, heat 3 tablespoons of the oil until shimmering, 1 to 2 minutes.
2. Add the onions and stir to coat. Cook, stirring occasionally, until the onions soften and release some moisture, about 5 minutes.
3. Reduce the heat to medium-low and cook, stirring frequently, until the onions are deeply browned and slightly sticky, 30 to 40 minutes longer. (If the onions are sizzling or scorching, reduce the heat. If the onions are not browning after 15 to 20 minutes, raise the heat.) Set aside.
4. Meanwhile, in a large pot over high heat, bring the potatoes, 2 tablespoons of the salt, 2 tablespoons of the vinegar, and the water to a boil.
5. Reduce the heat to medium and simmer until the potatoes are just tender, 15 to 20 minutes.
6. While the potatoes are cooking, mix together the grainy mustard, remaining 1 tablespoon salt, pepper, remaining 5 tablespoons vinegar, and remaining 1/3 cup oil in a large bowl.
7. When the potatoes are tender, drain and add immediately to the large bowl with the dressing. Gently stir to coat.
8. When the potatoes have cooled, toss with the caramelized onions, pea vines, Kalamata olives, scallion, and chile, and serve.
The salad can be refrigerated in an airtight container for 1 to 3 days.
