Salt and Vinegar Potato Salad

Peel and cut onion lengthwise into 1/3-inch wedges. Separate layers.

Toss together onion, 2 tablespoons vinegar, and 1/2 teaspoon salt in a bowl. Marinate at room temperature, tossing occasionally, until slightly softened and pink, about 45 minutes.

Cover potatoes with salted cold water in a 5- to 6-quart pot, then simmer, uncovered, until just tender, 15 to 20 minutes.

While potatoes cook, whisk together 2 teaspoons Old Bay seasoning with sugar, remaining 1 1/2 teaspoons salt, and remaining 1/2 cup vinegar in a small bowl.

Drain potatoes in a colander, and when cool enough to handle but still warm, peel and cut into 1/2-inch-wide wedges. Toss warm potatoes with vinegar mixture in a large bowl. Add onion mixture and oil, tossing to combine. Add more Old Bay seasoning (to taste) if desired. Serve warm or at room temperature.

Onion can be marinated, covered and chilled, up to 1 day.