PreparationMake dressing: Blend first 5 ingredients in processor. With machine running add oil in slow steady stream. Add cream; blend mixture until thick and creamy. Mix in herbs. (Can be prepared 1 day ahead. Cover and refrigerate. Bring to room temperature before using, thinning with water if dressing becomes too thick.) Make salad: Cook potatoes in large pot of boiling water until tender, abut 30 minutes. Drain and cool. Peel potatoes. Cut into 1/3-inch-thick slices. Transfer potatoes to large bowl. Sprinkle with cider vinegar. (Can be made 4 hours ahead. Let stand at room temperature.) Whisk oil and vinegar in another large bowl. Add lettuce and toss to coat. Add capers to potatoes. Mix enough dressing into potatoes to coat. Spoon potatoes atop greens and serve.
PreparationMake dressing: Blend first 5 ingredients in processor. With machine running add oil in slow steady stream. Add cream; blend mixture until thick and creamy. Mix in herbs. (Can be prepared 1 day ahead. Cover and refrigerate. Bring to room temperature before using, thinning with water if dressing becomes too thick.) Make salad: Cook potatoes in large pot of boiling water until tender, abut 30 minutes. Drain and cool. Peel potatoes. Cut into 1/3-inch-thick slices. Transfer potatoes to large bowl. Sprinkle with cider vinegar. (Can be made 4 hours ahead. Let stand at room temperature.) Whisk oil and vinegar in another large bowl. Add lettuce and toss to coat. Add capers to potatoes. Mix enough dressing into potatoes to coat. Spoon potatoes atop greens and serve.