The evening before, cover the beans with water and soak for about 12 hours. Drain and boil up with 1 l water. Simmer at low to medium heat for about 1 hour until the beans are soft.
In the meantime peel and chop the onion. Clean, wash and chop the celery. Put about 4 tbsp aside.
Heat 2 tablespoons of butter in a saucepan. Sauté onion and celery cubes in it. Add the cooked beans together with the liquid (only very little is left). Season with salt and pepper. Deglaze with a good 1 l water and cream.
Bring to the boil, stir in broth and simmer for 15-20 minutes.
In the meantime dice bread finely. Heat 1 tablespoon of butter in a frying pan. Add the remaining celery and roast for 6-8 minutes. Add bread cubes and roast for another 4-5 minutes. Season with salt and take out.
For the parsley and garlic oil, wash parsley, shake dry and chop coarsely. Peel and coarsely chop the garlic. Put both into a mixing bowl with the lemon juice. Add cumin, salt and chilli powder.
Puree with a hand blender and allow the oil to run in.
Remove soup from the stove and puree finely with a hand blender. Season to taste with salt and pepper. Sprinkle the soup with the croutons and sprinkle with the parsley and garlic oil.