In a small pot, heat the oil with butter, add the finely diced onion and fry occasionally stirring for about 2-3 minutes, add the garlic cut into thin slices and rosemary, fry for about 2 minutes.
Add the thinly peeled and diced Jerusalem artichoke and fry, stirring occasionally, for about 2-3 minutes. Then add the cauliflower cut into pieces, chickpeas and fry for another 2 minutes, gently seasoning with salt. Then pour the hot (!) stock and bring to a boil.
Cook for 15 minutes until vegetables are soft (they should not fall apart, be too soft). Blend the soup in a standing blender into a smooth cream, season with salt if needed.
Wash kale, cut the leaves from the hard center part, season with salt, pepper, coat in oil and arrange on a baking sheet. Bake for 10 minutes at 180 degrees C until crispy but not yet brown or burnt.