Soak the chickpeas for twelve hours in warm water with a teaspoon of baking soda, then rinse them and put in a saucepan with the celery, carrot and onion, previously cut into small pieces. Then add the garlic, the bay leaf and cover with plenty of water. Add salt and cook for about two and a half hours. When the chickpeas are cooked, blend and filter them.
Put the cod fillets in water for about 30 minutes, in order to desalt it. Then season them with grated lemon, thyme and a little of extra virgin olive oil and steam for about 9 minutes.
Put the black chickpeas soup at the base, then place the cod on top and garnish with fresh thyme and lemon zest.
Soak the chickpeas with a teaspoon of baking soda to soften the skin (cellulose). The water should be three times the volume of chickpeas.