Preparation

• Soak the chickpeas in 8 cups cold water in the refrigerator for at least 8 hours and up to 24 hours. Drain.
• In a large, heavy-duty pot, cook the chickpeas and baking soda over medium heat, stirring often, for 3 minutes. Add 8 cups fresh cold water and the garlic and bring to a boil. Immediately reduce the heat to a simmer and cook until the chickpeas are very tender throughout, about 1 hour. Reserve 1/4 cup of the cooking liquid, and then drain the chickpeas.
• Transfer the chickpeas to a large bowl, and cover with cold water. Gently agitate the chickpeas with your fingers to help dislodge the skins. Stir with a skimmer or slotted spoon, and remove the skins as they rise to the surface. Drain well. Reserve 2 Tbs. of the chickpeas, and transfer the rest, including the garlic, to a food processor. Purée until the mixture balls up.
• With the machine running, add the tahini, lemon juice, salt, and chickpea cooking liquid through the feed tube. Scrape down the sides, and purée until very smooth. Transfer to a bowl, cover, and refrigerate at least 30 minutes and up to 3 days. The hummus thickens and the flavors develop as it sits.
• Just before serving, season to taste with more salt and lemon juice, if necessary. Use the back of a spoon to create a well on the surface of the hummus and drizzle on the olive oil. Scatter the fava beans, reserved chickpeas, parsley, and za’atar over the top, and serve.