Roast pine nuts in a pan without fat until golden brown. Remove. Peel onion and dice very finely. Wash cress and cut from the bed. Drain the capers.
Mix cream cheese, sour cream and onion. Season to taste with salt and pepper. Divide the mixture into thirds.
Coarsely chop the pine nuts and stir into a portion of cream cheese cream. Stir the cress into the second portion of cream cheese. Coarsely chop the capers and stir into the rest of the cheese cream. Sprinkle with paprika powder.
Peel and wash the potatoes and cut them into approx. 12 thick slices. Dab potatoes dry well. Heat oil in a large coated pan. Fry the potato slices for 10-15 minutes while turning them until crispy.
Season with salt and pepper. Remove and drain well on kitchen paper. Arrange potato crostini with the cheese dips.