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

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

Meanwhile, prepare dressing. Insert steel knife. Combine 3 tablespoons oil, egg, mustard, dill, vinegar, lemon juice, salt, sugar and pepper and blend until mixture is slightly thickened, about 10 seconds. With machine running, slowly pour remaining oil through feed tube in thin, steady stream and mix well. Add sour cream and blend 3 seconds to combine. Remove and set aside. Do not clean work bowl. 8 servings.

Thick Slicer: Slice potatoes while still warm, using light pressure. Stand celery in feed tube and slice, using light pressure. Transfer vegetables to large bowl. Add enough dressing to coat lightly; toss gently. Adjust seasoning.

Thin Slicer: Slice onion, using firm pressure. Add to salad just before serving.