Chickpeas soak in water the night before. The next day, drain the water, pour a new and boil for half an hour or until ready (I use a pressure cooker). Drained while retaining about 400 ml water in which it is cooked. In large skillet heat 3-4 tbsp of olive oil. Add onions and cook on medium to low heat for 20 minutes until soft and caramelized completely. Stir frequently. In a pan mix cooked chickpeas, caramelized onions, rosemary, bay leaves and remaining olive oil. Add salt with salt and freshly ground black pepper (to me without pepper). All pour the separated water from boiling chickpeas, so as to cover almost entirely. The tray is placed in a preheated oven at 180C and the dish is cooked for about one hour or half an hour until it became a brown color on the surface and the bulk of the liquid has evaporated. Serve warm or at room temperature. When cool the sauce thickens.