Start with preparing the base of the soup by heating up in a pot 3-4 tablespoons of olive oil, adding the chopped onion, carrot and celery (also crushed garlic if using) and frying on a medium heat for about 10 minutes until the onion turns translucent.
Drain he chickpeas. Add roughly 2/3 of them into the pan followed by the cubed potato.
Give it a stir and fry all together for a few minutes add the tomato pure into the pot. Now pour into the pot the stock of your choice to cover everything by 2-3 cm. If you add to much stock the soup will turn watery. You can always add more at a later stage.
Cover with the lid and cook on a low heat until all vegetables have turned soft, it should take you about 30-45 minutes (depending on the size of the chickpeas).
Once the vegetables are soft turn the heat off and let them cool for a few minutes.
Now pour the cooked vegetables with the stock into a blender and turn into a creamy liquid.
You could use a hand blender instead.
Pour the liquid back into the pot, add the reserved chickpeas, rosemary sprigs (tied with cooking twine as it is easier to remove them later on that way) and a pinch of salt.
Cooked covered with the lid on a small heat until the chickpeas are cooked through and soft stirring occasionally.
Season with salt and black pepper towards the end of cooking the soup.
The chickpea cream works extremely well served drizzled with some good olive oil and with warm toasted or grilled bread on the side.