Roast pine nuts in a pan without fat for about 2 minutes. Take out and let cool down. Clean and peel the celeriac, cut it into thin strips. Clean, wash and cut the celery in thirds and cut into fine strips. Peel and wash the carrot and cut into thin strips. Lightly crush the pine nuts and mix with the vegetables
Mix double cream, yoghurt, vinegar and olive oil. Season to taste with salt and pepper. Pour dressing over the vegetables
Wash the apple, grate dry, cut into thin slices and sprinkle with lemon juice. Wash the chervil, shake dry, pluck the leaves from the stalks. Brush each slice of bread with 1/2 teaspoon butter. Spread 2 apple slices, 1 slice of Parma ham and 1/4 Waldorf salad on each slice of bread. Sprinkle with chervil