Clean, wash and pluck the frisée into bite-sized pieces. Clean, wash, quarter and seed the tomatoes. Cut the flesh into small cubes. Chop walnuts. For the marinade, mix vinegar, salt and pepper and add oil.
Mix the frisée, tomatoes and nuts with the marinade and leave to stand. In the meantime mix cream cheese and quark. Pour into a piping bag with star-shaped spout and squirt in portions on pumpernickel slices. Serve garnished with parsley