Preparation In a 3-quart kettle cover potatoes with cold salted water by 2 inches and simmer until potatoes are tender but resist when pierced with a fork, about 20 minutes. Drain potatoes in a colander. When potatoes are just cool enough to handle, peel and cut into 1/4-inch-thick rounds. While potatoes are still warm, layer one third in a large serving dish or bowl and drizzle with 1 tablespoon vinegar. Season potatoes with salt and pepper. Continue layering in same manner with remaining potatoes and vinegar, seasoning with salt and pepper. Peel, quarter, and core apples. Cut quarters crosswise into 1/8-inch-thick pieces and in a bowl toss with lemon juice. In a small saucepan simmer apple juice until reduced to about 3 tablespoons. In a bowl beat cream until it just holds soft peaks and gently but thoroughly fold in reduced apple juice, mayonnaise, parsley, Calvados, and pepper. Season sauce with salt and gently toss together with potatoes and apples.
Preparation In a 3-quart kettle cover potatoes with cold salted water by 2 inches and simmer until potatoes are tender but resist when pierced with a fork, about 20 minutes. Drain potatoes in a colander. When potatoes are just cool enough to handle, peel and cut into 1/4-inch-thick rounds. While potatoes are still warm, layer one third in a large serving dish or bowl and drizzle with 1 tablespoon vinegar. Season potatoes with salt and pepper. Continue layering in same manner with remaining potatoes and vinegar, seasoning with salt and pepper. Peel, quarter, and core apples. Cut quarters crosswise into 1/8-inch-thick pieces and in a bowl toss with lemon juice. In a small saucepan simmer apple juice until reduced to about 3 tablespoons. In a bowl beat cream until it just holds soft peaks and gently but thoroughly fold in reduced apple juice, mayonnaise, parsley, Calvados, and pepper. Season sauce with salt and gently toss together with potatoes and apples.