• ½ pound red potatoes, quartered
• 1 (15-ounce) can small white beans such as Great Northern
• 1 small sweet yellow onion or red onion, cut into paper-thin slices
• 1½ tablespoons white wine vinegar
• ½ teaspoon salt, or to taste
• ¾ teaspoon ground cumin
• 1 garlic clove, crushed in a garlic press
• Freshly ground black pepper to taste (optional)
• ⅓ cup extra-virgin olive oil
• ¼ cup chopped fresh parsley, preferably flat-leaf parsley
• Watercress or lettuce leaves

Put the potatoes in a saucepan with enough lightly salted water to cover by 2 inches. Bring to a boil over medium-high heat. Reduce the heat to medium-low and boil gently until tender when pierced with the tip of a knife, 20 to 30 minutes. Meanwhile, drain, but do not rinse, the beans and place the onion slices in a bowl with ice water to cover.

In a salad bowl, whisk together the vinegar, salt, cumin, garlic, and pepper. Gradually whisk in the oil.

Drain the potatoes, and when cool enough to handle, peel and cube them. Drain the onion slices. Add the potatoes, beans, onion, and parsley to the salad bowl and toss gently. Chill or serve at room temperature. Serve the salad surrounded by watercress leaves.