Warm Yellow Potato Salad

Fill a large saucepan with the whole unpeeled potatoes, water to cover them by 2 inches, and a generous pinch of salt; bring the water to a boil. Cover with the lid and boil the potatoes for 30 minutes, or until the potatoes are tender when pierced with a skewer. Add more boiling water to the pot, if necessary, to keep the water level up.

With tongs, remove the potatoes from the pot and set them on a board. Let them sit for 5 minutes. Cut them into 1/4-inch slices. Arrange half the potatoes on a shallow platter. Sprinkle with 1 tablespoon of the vinegar, salt, and pepper. Layer the remaining slices, 1 tablespoon vinegar, salt, and pepper. Set the potatoes aside for 5 minutes.

In a bowl, whisk the remaining 2 tablespoons of vinegar, another pinch each of salt and pepper, and mustard. Whisk in the oil a teaspoon at a time until the dressing emulsifies.

Pour the dressing over the potatoes, sprinkle with parsley, and top with the sliced green onions. Serve warm.