Drain the water and cook the chickpeas with a potato for 30-40 minutes. Clean the leek and cut into fine strips. Put the oil in a saucepan and fry the two finely chopped garlic cloves. Add the leek and fry until the leek collapses. Add the cooked chickpeas and pour in approx. 850–1000 ml of stock. Let it cook for 15 minutes.
Mix about half of it finely with a blender and add again. Fold in the parmesan cheese.