Lemon-Arugula Potato Salad

This refreshing potato salad is perfect for a summer backyard barbecue and goes perfectly with almost any main course.
Place the potato slices in a medium-sized saucepan; cover with cold water 2 inches above the potatoes. Bring to a boil over medium-high heat. Reduce the heat to medium and simmer for 10 minutes or until the potatoes are tender. Drain the water from the potatoes.Preheat a small skillet over medium-high heat. Add 1 teaspoon of oil to the skillet; stir to coat. Add the shallots to the skillet; saute for 3 minutes or until lightly browned, stirring occasionally. Remove from heat. Combine the shallots, vinegar, mustard, lemon zest, lemon juice, salt and black pepper in a small bowl, stirring well with a whisk. Gradually add the remaining 2 tablespoons of butter, stirring constantly with a whisk until smooth. Drizzle the sauce over the warm potatoes; stir gently to coat. Allow to cool completely.Add the arugula to the potato mixture; mix gently. Serve immediately.