In food processor or blender, combine trout, dill, butter, lemon juice and hot pepper sauce; process until smooth. With machine running, gradually add cream through feed tube, processing until smooth and creamy. Add tomato paste; process just until blended.
Spoon mousse into serving dish. Cover and refrigerate for at least 1 hour or until chilled. Makes about 1-1/2 cups (375 mL).