Mix trout, apple, celery, and chives in large bowl to blend.Whisk sour cream, mayonnaise, and ½ c Terrapin Ridge Farms Apple Horseradish Jam in small bowl to blend. Fold horseradish mixture gently into trout mixture (do not break up trout). Season to taste with salt, pepper. Can be made 1 day ahead. Cover and refrigerate. Transfer trout mixture to serving bowl and place on platter. Surround with toasts and serve.