Peel, wash and roughly chop the celery and potatoes. Peel and chop onion and garlic. Heat 1 tablespoon butter in a large pot. Stir-fry the celery, onion and garlic for about 5 minutes.
Add the potatoes and 1 l water. Season with salt. Bring everything to the boil, cover and simmer for about 20 minutes.
Meanwhile wash parsley, shake dry, pluck off leaves and chop finely. Chop the nuts finely. Dice bread. Heat 1 tablespoon of butter in a frying pan. Fry the bread cubes for 4-5 minutes while turning them until crispy.
Briefly roast the nuts as well. Season with salt and pepper. Stir in honey and parsley.
Finely grate the cheese. Puree the soup finely with a hand blender. Melt cheese in the soup. Stir in crème fraiche and simmer for about 2 minutes. Season soup with salt, pepper and nutmeg and serve with the croûton mix.