Cut loaf lengthwise into 4 slices. Spread 3 slices with margarine. In small bowl, combine all filling ingredients; mix well. Spread 1/3 of filling over margarine on each slice of bread. Stack slices on serving plate, placing plain slice on top.
In large bowl, combine cream cheese and half-and-half; mix well. Spread over sides and top of loaf. Cover carefully with plastic wrap; refrigerate at least 2 hours.
Just before serving, garnish with chopped parsley and cashews, if desired. Store in refrigerator.