Cut 1 ½ lbs red and/or Yukon potatoes in equal-sized pieces. In a medium saucepan, parboil until just fork-tender, but firm. Allow to cool.
Combine 2 Tbsp. Dijon mustard, 2 Tbsp. apple cider vinegar, 2 Tbsp. sugar, 2 Tbsp. extra-virgin olive oil, 1 Tbsp. chopped fresh dill, and salt and pepper to taste. Mix in 1 Tbsp. capers and set aside. Grill potato halves on a grill pan over medium-high heat about 4 minutes or until browned. Turn over and cook the other side. Try to get nice grill marks on them. Toss potatoes in dressing until well-coated. Add ¼ small red onion, thinly sliced, and 2 chopped ribs of celery and toss everything together. Enjoy warm or cold, on a bed of arugula or chopped lettuce.
We thank onegreenplanet.org for this recipe.