Drain chickpeas and rinse. Place half of chickpeas in a large pan and pour in 5 cups of water. Add half of the onion, bone and garlic cloves. Bring to a boil and simmer until chickpeas are very tender.
Remove bone from pan. Purée mixture in food processor until smooth. Return to pot. In another pot, cook the remaining chick peas in 4 cups of water until very tender. Drain and remove skins if you wish. Add to chickpea purée.
Heat oil in a pan and sweat the minced garlic and the remaining onion until translucent. Add chopped up spinach or Swiss chard and stir until wilted. Stir this mixture into chickpeas. Pour in chicken stock, place over medium heat and simmer until heated through. Taste and season with salt and pepper.
For a really spicy version, seed and chop 1 or 2 fresh or dried red chillies and add to soup. Serve with a good drizzling of extra – virgin olive oil and a generous sprinkling of Parmesan cheese. A dollop of Spinach Pesto tastes especially good with this soup. Happy winter days!