How to Make It
In a medium bowl, cover the chickpeas with 1 inch of water and stir in the baking soda. Let soak overnight.
Drain and rinse the chickpeas. In a medium saucepan, cover the chickpeas with 1 inch of water and bring to a boil, skimming as necessary. Cook the chickpeas over low heat until very tender, about 40 minutes. Drain the chickpeas, reserving 1 cup of the cooking liquid.
In a food processor, puree all but 1/4 cup of the chickpeas until smooth; add some of the reserved cooking liquid if the puree is dry. Add the tahini and lemon juice and process until satiny. Add more of the reserved cooking liquid until the consistency is that of sour cream. Transfer the hummus to a bowl.
Remove the skins from the reserved chickpeas. Mash the garlic with the salt until smooth. Stir the garlic into the hummus and transfer to a shallow bowl. Add the parsley to the olive oil and drizzle it over the hummus. Garnish with the whole peeled chickpeas and serve.