4 qt. water, salted
2 lb. red new potatoes, unpeeled
3/4 c. vegetable oil
1 egg, at room temperature
3 tbsp. Dijon mustard
2 tbsp. snipped fresh dill or 2 tsp. dried
1 tsp. red wine vinegar
1 tsp. fresh lemon juice
1 tsp. salt
1 tsp. sugar
Freshly ground pepper
1/2 c. sour cream
3 med. celery stalks
1 med. onion

Bring salted water to a boil over high heat and cook potatoes. Reduce heat and cook just until potatoes can be easily pierced with the tip of a sharp knife; do not over-cook. Potatoes will will be slightly firm. Drain immediately. Cover with cold water and let stand exactly 8 minutes. Drain potatoes well.

Meanwhile, prepare dressing. Insert steel blade into food processor. Combine 3 tablespoons oil, egg, mustard, dill, vinegar, lemon juice, salt, sugar and pepper and blend until mixture is slightly thickened, about 10 seconds. While machine is running, slowly pour remaining oil through the feed tube in a thin, steady stream; mixture will thicken. Add sour cream and blend for 3 seconds to combine. Remove and set aside. Do not clean work bowl.

Makes 8 servings.

Insert Thick Slicing blade into food processor: Slice potatoes while still warm, using light pressure. Stand celery in feed tube and slice, using light pressure. Transfer vegetables to a large serving bowl. Add enough dressing to coat lightly; toss gently. Adjust seasoning to taste.

Insert Thin Slicing blade into food processor: Slice onion, using firm pressure. Add to salad just before serving.