1.Par-cook potatoes in a saucepan of salted boiling water, 10-15 minutes, or until just tender. Drain well and allow to cool. Cut into thick slices.
2.In a serving bowl, combine apple, celery, raisins and nuts. Set aside.
3.For dressing, place all ingredients in a food processor or blender and process until smooth. Season to taste.
4.Heat butter and oil in a large frying pan on high. Sauté potatoes and frankfurts, 5-10 minutes, until potatoes are tender and golden. Drain on paper towel. Cool slightly.
5.Toss potatoes and frankfurts through salad with dressing. Serve.